text:
Why doesn't Germany just raise its requirements to get into a university course?
As a follow up to this question: If large population of students in German universities are failing anyways, why not just require an entrance test for courses? Is there any reason Germany hasn't implemented this?
(Edit) I realize I should have elaborated why I recommended testing. In the place where I come from(India), well more like in 90% of Asian countries, testing is a critical part of process of getting into university. In the particular place I come from, one could argue that the emphasis on testing arises from an actual lack of university seats, but even if one talks of more developed Asian countries, for example, Korea and China, still you'd find the same. For example, the suneung  or Gaokao in China.
And, I have an interest to study in Germany, and hence the questions arose as an interest to know why things are the way are in this country.

A more realistic framing would be helpful: it's certainly not correct that "most people in Uni are failing" in Germany.

Quite apart from the legal aspects highlighted in the answers so far: Is there a test that validly and reliably predicts success in studying math? I am not aware of one, and school grades in math IMO certainly are not sufficiently predictive - I see too many kids with the best possible grade in math, who would almost certainly fail the first semesters. Given that the two last years of Gymnasium have so little predictive power, I am skeptical that there would be a simple one-day test that does any better. Which kind of undercuts your proposal, no?

@StephanKolassa: Ironically, my university disposed of all placement testing a few years ago, arguing that grades from the last years of high school could certainly be used with sufficient predictive power. And then (cough) had to walk that back after seeing the results from those few years.

@DanielR.Collins That's how it worked where I am and I graduated high school in 2003. Are you from a place where the high school curriculum is really varied and not mandated across the board?

@DKNguyen: I'm in the U.S. where that's the normal situation. In addition, around half or more of our incoming students are from foreign countries.

@DanielR.Collins That explains it. In the US things go by state and sometimes not even that so the standards are all over the place. It's the same reason why everyone has to take a PE exam, because the accreditation of the different universities and colleges are all over the place.

@TrystwithFreedom Your question has an aggressive/arrogant tone. Remove the "just" and rephrase "large population .. is failing anyways" to "having a high fail rate", to make it more objective and calm.

Another small part to an answer: Organizing entry tests is work. Someone has to prepare them, the students have to travel to take them and then they have to be graded, all with the start of the semester approaching. In many subjects, it is simply easier to admit everyone. If there are mostly lectures, it makes little difference in workload whether you have 100 students or 150 students in your class. So even if it would be allowed (which it is not by Hennings answer), there would be an argument not to have any entry tests.

@TrystwithFreedom: You have asked several questions related to this topic, and repeatedly received answers and comments that ask you to specify your premises (e.g., what does it mean to fail) or address this question tangentially (e.g., on the very question you link). Due to this it is fair to expect that you take this into account in a new question, cover the basic background yourself (so the answers don’t need to start from scratch), elaborate your skepticism on the known arguments, and similar.

Tests do not accurately judge if someone is going to do well at college or not as there are other factors that impact that. There is a reason that colleges are starting to drop tests as part of the admissions process.

"I have an interest to study in Germany, and hence the questions arose as an interest to know why things are the way are in this country." Please read https://meta.stackexchange.com/questions/66377/what-is-the-xy-problem carefully and make sure you are not asking this type of question. Instead, ask about your actual problem you want to solve, otherwise you will not likely get answers that actually help with your problem. What is the problem here that you face? Is it that you are worried you will be accepted to study at a German institution and then fail?

Suneung and Gaokao have very deep historical and cultural roots in (North-)East Asia. I see no reason to expect a similar tradition anywhere in Europe.

Well, that's a personal question. I have no real problem in sense of something that would effect my life directly here, I am simply asking out of curiosity in understanding the system as I have said @BryanKrause. Furthermore, those discussions are off topic here to my understanding; undergraduate admission advice

There are a number of reasons, but the most important one is that the German constitution, the Basic Law, guarantees the freedom to chose one's profession as a fundamental right in Art. 12 (1.1).
Based on this provision, Germany's Federal Constitutional Court strictly limited the legal room for maneuver for restrictions on access to public universities in the famous Numerus Clausus Judgment of 1972 (BVerfGE 33, 303). Since then, the jurisprudence has evolved, but generally speaking, limitations such as minimum admission grades (sometimes not quite correctly referred to as Numerus Clausus) are only permitted when there is a demonstrable shortage of positions that cannot be fixed in the short term. In general, everybody with Abitur must be given the same access to a place to study.

Edit by @ccprog, as invited in the comments: I'd like to add a few details about the actual procedures.

There are two seperate processes for admission to programs with restricted access: a central admission for all German universities by contract between the state governments, and local admission on proposal by individual universities and governed by state regulations.

Both types are under the restriction to actually prove that the number of admissions are really exhausting the university's capacity to teach students. From my own time involved in these matters, I know that universities each year had to admit 10% or more above the initial numbers on court orders. (There are actually law firms that make a living on asserting admittance for refused applicants on these sort of grounds.)

The Numerus Clausus might not be the sole basis of admittance. Most states have laws that allow additional criteria besides the Abitur grade. As an example, in Berlin universities first fill 20%–30% of the places with reseved quota like foreign students and applicants with a completed vocational training. Then, at most 60% of the places are filled by admittance criteria determined by the university and approved by the state administration. All other places are filled according to the Numerus Clausus and the number of semesters the applicant had to wait since his first petition ("waiting time").
Mind you, most universities don't bother to design special admittance criteria and just use the Abitur grade for everyone. First, short of interviewing everyone individually the results probably won't differ, and second, it is just too costly to do all this testing.

@TrystwithFreedom Why should it? That would be stupid - making degrees passable by everyone would totally devalue them as they would need to be so basic that it is useless.

The right to chose one's profession doesn't extend to a right to graduate. It's only a right to study and take a shot at graduation.

@TrystwithFreedom The law is basically there to give everyone the OPPORTUNITY to enroll in the course they want, not the GUARANTEE that they will earn a degree

That i understand, but that is nt the point I mean. How does my interpretation of the law fail? @Sursula. Does the legal system justify it? Or, is it just accepted that my itnerpretation is wrong generally?

@TrystwithFreedom it's generally accepted that the right doesn't extend to a prohibition of meaningful exams or a right to graduate. I'm not a lawyer, so I can't explain where the judgement drew the line and why. I'm sure there's a translation somewhere, or you could ask over at law.stackexchange

@TrystwithFreedom the law is there to give everyone who has the capabilities to do a certain job the opportunity to do it. Yet, it doesn't want to give inept people a degree (e.g. a person who faints at the sight of blood shouldn't be a surgeon and will rightfully fail any practical exam), but it lets everyone TRY to be anything.

@TrystwithFreedom and of course giving everyone the opportunity does not equal equal opportunity, as rich people might be able to hire private tutors etc.

@Sursula: An American interpretation of the right to try to be anything would tend to suggest that there should be no licensing restrictions - someone can try to be a doctor without any qualifications - if they then kill a few patients they'd get sued or possibly go to jail.  The government shouldn't make any restrictions, only the market, and maybe the courts after the fact if clear harm was done.

@AlexanderWoo the American interpretation probably wouldn't create an obligation on the state to provide a free service, though. :)

While I'm not 100% certain, this section in the constitution was likely introduced to make a statement about individual freedom that wasn't necessarily present before the German constitution existed (aka before 1945...), meaning that back then some people were forced to take up certain jobs - which would also be in the spirit of Art 12 (2).
Funny though how it's washed down in sec. (3) ...
It's certainly not a free pass to graduation.

This answer suggests that requiring certain minimum grades (for entry) would constitute a Numerus Clausus. I don't believe that is the sense of the latter term, which refers to a limitation on the number of people admitted; it implies that one can be refused not for failing any particular admittance criterion, but simply because the number of places is exhausted. The mechanism of Numerus Clausus itself does not say by which criteria the available places are allotted; it could be anything from an entrance competition to a lottery.

@MarcvanLeeuwen while you're correct about the meaning of the literal translation from latin, in the context of the German discussion about university admissions and about the ruling in particular, numerus clausus refers to a threshold grade required for admission. But I've changed the phrasing to make it also technically correct. Thanks!

@henning Not completely true. Most state laws now contain clauses that allow additional criteria for selection, provided the Abitur grade remains a prominent factor. It is just that most universities don't bother with the effort when results probably won't differ.

@ccprog Feel free to edit the answer. I sure I glossed over many details.

@AlexanderWoo I very much hope that in the US you need a license or degree of some sort to become a doctor, and not just "as long as you haven't killed anybody yet, you're good to go. :P

How does the (now abandoned?) "Medizinertest" fit in your narrative?

@user151413 it seems that it has been abandoned for essentially the reasons given in the answer, after the Court further specified how an assessment that would comply with its previous rulings should look like https://www.bundesverfassungsgericht.de/SharedDocs/Pressemitteilungen/DE/2017/bvg17-112.html

First: Most people don't fail university in Germany, it is very much dependent on the topic.
Concerning your suggestion of an entrance exam: education is a state-level competence in the federal system of Germany, that is each of the 16 Bundesländer can decide on how primary and secondary education is organized in their state (of course not completely but to a certain extent). As a result the levels of knowledge in certain subjects at Abitur level varies considerably between the Bundesländer. As an example, when I started studying, my Abitur math level from southern Germany was such that almost all of the first semester Analysis 1 course I already knew from school while some of my co-students from other Bundesländer hadn't heard any of it before.
Due to this federal education system, implementing generalized entrance exams would be very unfair and would skew the admittance in favor of those that were more "lucky" in where they grew up.

I have to say,  I am quite jealous given how things are Indian. Here people, say who cares, and put a uniform exam although there are different expectations by each Bundesland

@TrystwithFreedom - that, of course, assumes the entrance exams are meaningful in predicting how one might do in university in some particular area. And also assumes a uniform quality of instruction across the whole country. Both are unlikely.

To add to this: Even if everybody received the same math education in high school, this would strongly differ from what university mathematics requires. Any test on high-school maths (including high-school grades) are a flawed predictor for the capability to study maths. And this becomes even worse for fields like law, pedagogics, economics, geology, or engineering, which have no high-school equivalent (at least at most high schools).

the current system is also unfair because people with the same capabilities have different grades based on where they grew up, aka equally viable candidates are treated differently

@Hobbamok That is true, but unless people are thought by robots, there is no completely fair system as even with the exact same curriculum, teacher quality etc. will vary

The British system relies heavily on grades and occasionally (which is even worse, as it mainly tests for big egos) interviews. I work at what is nominally one of the best universities in the UK and the number of students we drag through that had the grades at school, but not really an ability for the corresponding university course is astounding. The German system (which has very low fees, so it's not like you lose $10000 if you start over again after a year) really works much better to filter out the people that will actually succeed at university.

henning has already given the most important answer why nobody bothers to take the legal hurdles.
A few other practical or political hurdles include:

The top-tier high school diploma (Abitur) is generally regarded as a sufficient selection criterion to avoid an overflow of students. That being said, you can also enroll at a university if you complete a vocational training, with details left to the states and universities.

Implementing another countrywide admission test would meet political opposition: it costs money, it would be considered too bureaucratic, and meet opposition by angry middle class parents. And if any politician dares messing with their kids' Abitur, they get very, very angry.

That being said, the Abitur isn't a perfect selection criterion either. It's considerably easier to get in some parts of the country due to uneven educational policies in each state. A national college entry exam (similar to SAT in the US) would meet with opposition by the lower-ranking states. The pressure isn't that high since most students don't move too far away from their home area, typically staying within their state.

In that sense, the college entrance exam is basically deferred to the individual university. It's not uncommon to switch programs after a semester or two, and I know people who enrolled in several programs for the purpose of checking them out.

Another important difference to the US, India, or China: the quality of the universities is much more even. There are a few top-tier universities but generally speaking the variability in quality of the programs is not nearly as huge as in other countries. The reasons are probably political/historical. Generally speaking, a 'university' in Germany compares to an R1 college/university in the US.

Thank you for that edit.

Why should they?
Your base assumption in that question is that a) many people failing early on is bad and b) a universal entry exam would somehow change this.
Regarding a) : A lot of courses (usually those with ease of providing high capacity because no practical stuff is necessary) intentionally have a low barrier of admittance (because they have capacity this is constitutionally required), but make up for that by challenging the students intensely in the first couple of semesters (causing many to fail). This is not a bad thing. It doesn't judge people on the performance on a singular day & test but instead on their ability to (and implied likelihood of) finish the course. This also allows for students with bad school performance to get their act together and ignores failure in fields irrelevant to the actual studies. If you CAN admit a lot of people (because the first few semesters allow for mass processing of students), why wouldn't you?
b) a universal entrance exam (completely universal like the Chinese one or per-subject?) wouldn't change this without exorbitant cost in terms of students that would have made the course but failed the exam. If the bar for this test is set too high, it is unconstitutional may fail people because of irrelevant subjects (a math-focused student might fail the German part for example) or for poor performance years past. It also prevents people from checking out a subject and deciding for themselves that they either dislike it, or have to work harder for it than previously. Especially the latter is impossible with a test you likely can take once as a teenager when you didn't really care for education (or for a specific field that in the end motivates them to try hard enough).

There are some subjects that have restrictions like this, mostly those with limited capacity like medicine. For those your final high school grade (Abitur) are typically used, which likely results in a selection similar to the one some aptitude test would create.
My impression is that this is simply not seen as a problem. It is arguably a more fair system than the alternatives. Your ability to succeed in the subject is measured by the actual courses and not by a proxy like some general aptitude test or by some subjective and potentially biased manual selection of candidates.
Difficult subjects also tend to put some of the difficult parts into the first semester, so you will usually know pretty quickly whether you're doing well or not. It does waste some time for students that pick a subject they don't succeed in, but usually not too much of it. And university is free in Germany, so the financial consequences are limited.

The other answers do not explicitely mention this, but in some fields it has actually been common for decades to have some rather strict secondary school grade requirements. E.g. in medicine, veterinary medicine, psychology, architecture etc. That is the numerus clausus mentioned in henning's answer.
For several years it has also been common to supplement this requirement for good Abitur grades with entrance tests, at least in medicine (source in German, though arguably in the arts some kind of entrance testing has been common for decades).
Most STEM fields except biology do not have such requirements because demand for student positions is not so high most of the time. A high rate of failure then usually means that the field is inherently very difficult. However, it is sometimes alleged that exams are made more difficult if the number of first-term students is much higher then expected, in order to have fewer students in the later terms.

"it is sometimes alleged that exams are made more difficult" Hmm, made more difficult by whom? Due to the legal, organizational and cultural structure of German universities it is unlikely that this occurs at an organized level. Professors have a very high degree of freedom in designing and grading exams, so a department cannot simply enforce that a specific exam is made more difficult in a certain year. So while it might sometimes happen that a misguided individual instructor raises the difficulty of an exam due to a higher number of students, this in unlikely to occur systematically.

Re "A high rate of failure then usually means that the field is inherently very difficult" I'm not completely convinced. Sometimes I'm under the impression that the difficulties of many first year students in mathematics are not so much due to some inherent difficulty of the topic but rather due to a large discrepency what is required (in terms of work effort, learning strategies, and motivation for the topic) to succeed in maths and what many students believe were required.

@JochenGlueck this might even be done by individual professors, without any organization – they themselves are the ones to have to deal with a larger or smaller group later.

@JochenGlueck During my time at university, there were always rumors that one professor or the other was trying to use a certain exam (General mechanics for engineers, for example) to unfairly weed out the student body. It was also alleged this was with tacit approval by the faculty.

Western vs Eastern State Sponsored Education
What you are describing is a very common phenomenon in Western style public education as a whole, not just Germany. Despite socialized college education, Germany is still by-in-large a capitalist country in the way that it manages its public services.  In most Western school systems, the government pays for tuition and grants, not directly for the operating costs. When the government only pays for tuition, it means that the schools still need to compete for funding, and the most important metric for determining funding is how many students you serve.
For example, if you have the facilities and staff for 5000 students, but only 3000 pass the entrance exams because they are so difficult, then the school is still stuck paying for thier larger facility but with less income; so, it is in the best interest of the school to always fill every available seat.  So, to balance the budget, state sponsored universities set thier entrance requirement to the minimum it takes to guarantee 100% enrollment, not based on what it takes to complete the coursework. In the inverse case where a school has the facilities and staff for 3000 students, but they get 5000 who pass the entrance exams, then there is a financial incentive to accept over thier capacity, and use some of the extra funding to expand thier facilities until they can host 5000 students.  In this way, there is a supply-demand function in the way Western schools operate that encourages them to always accept the maximums number of students that they can and to grow to the capacity of the market.
In contrast, Eastern states operate based on the Communists economic model in which schools are given a fixed budget and are required to function within it.   So, if an Eastern school is budgeted to serve 3000 but has 5000 applicants that should be able to complete the coursework, then they are not able to collect 5000 tuitions from the State and use the money to expand the school system.  Instead, they can only accept the best 3000 until the government chooses to expand thier funding.  On the inverse, where they have 5000 seats and only get 3000 applicants that can pass the entrance exam, there is typically no penality for only accepting those 3000 applicants because they are still doing thier jobs within the budget allotted.
This puts the financial incentive for many Eastern Schools to operate by accepting as few students as the government will allow them to whereas Western Schools operate by accepting as many as are allowed.
A second major difference is the contrast between Populist Socialism and Communist Socialism. Communism Socialism which is most popular in East Asia is based on the original Marxist view that "From each according to his ability, to each according to his needs".  This means that Communist Socialists have no expectation that all people have the same abilities, opportunities, and needs which leads to a strong cultural bias toward only uplifting those who show merit.  In contrast, Populist Socialism which is the primary form of Socialism found in Western Nations, is based on the view that the government is responsible for making sure that all people have the same opportunities regardless of thier current ability and background.  This fundamental difference has influenced the goals and laws of the Western vs Eastern systems.
Germany Specifically
There is also a more recent cultural element to German education that they try to make it as non-competitive as possible.  Competitive learning environments are experimentally shown to reduce the effectiveness of education, and Germany is among the top nations when it comes to applying this principle. In Germany, there is a much greater belief that a person can fail one test, and still move on to achieve great success down the road, even when compared to other Western cultures.  So, while East Asian countries have built thier public education system around minimizing how much they need to invest, Germany has built thier system around maximizing the possible return on thier investment.

All the universities I know, not just the German ones, got their most of their financial support from the state based on the number of students, and it is nothing to do with capitalism.

@Greg Western school systems create availability in hopes of attracting students which brings in the federal/state funding; so, the school system theoretically grows until it reaches the capacity of demand, and schools cut back or fail when they exceed it.  This is basic supply and demand.   Communist school systems are first funded, and then students are allocated to them.  No matter how many people want to go to college in a Communist Country, the capacity is dictated by the State which they typically set much lower than the demand to prevent waste.

You are struggling with several misconceptions: 1) the world is not like Western Capitalists vs. everyone else Communists. 2) Unconditional state funding to meet everyone's needs is a core of communism, so in that sense, the education system in most EU countries is far closer to communist/socialist ideas than to capitalists 3) Higher education doesn't just grow and shrink according to demand even in EU. Simply the state cares enough to build enough space for everyone, not just for the rich kids who had enough money to do all the special preparation schools.

@Greg 1) Since the OP established East Asia as a cultural zone for reference, that is the level of division my answer is based off of. Yes, each country is unique, but there are also cultural normatives that happen at the larger scale based on shared history and values. 2) THAT the state funds education in Germany is Socialist, HOW the state allocates its resources is based on Capitalism, and WHO it aims to educate is Populist.  Communism in no way demands that all people be educated or have access to everything.

Karl Marx famously described his system as "From each according to his ability, to each according to his needs" such that not everyone is expected to have the same abilities and needs in a Communist State.  3) The overall budget may be set, but where the budget goes is based on enrollment, not based on how a Central Authority has allocated it.  I'm not talking about the German school system as a whole, but the individual choices made by German admissions personnel based on the framework that they must operate within.

Actually a study by the German Academic exchange service made a similar conclusion on reducing the drop out rates:

Die Phase vor der Ankunft in Deutschland sowie die individuellen
Erwartungen und Motive der internationalen Studierenden werden bislang zu
wenig beachtet pg -58
The phase before the arrival in Germany and the individual motives and expectations of international students are not considered yet.

Eine Verschärfung der Zulassungskriterien wäre ein einfacher, aber
nicht unproblematischer Weg zur Senkung der Abbruchquoten bei internationalen
Studierenden. pg-60
Enforcing stricter acceptance criteria would be an easy, yet not unproblematic way of lowering the drop-out quota of international students.

Furthermore, they have made later in the document a classification of the type of students who fail in their studies after coming to Germany with a detailed analysis.

Would that DAAD study per chance be this Internationale Studierende in Deutschland zum Studienerfolg?

Yep @semmyk-research

Germany has its own culture and cultural preferences, so comparing it to examples from different continents makes not much sense.
Irrespective what Germans think the general benefits can be:

Above a certain level, tough entrance examinations just moderately correlate with the ability of students to be productive professionals.
Strict entrance rules often tie down students to a certain education path, while many prefers course during to uni years, taking up new majors etc.
Strict entrance exams often create wrong incentives to students, favors rich kids with private tutors, and there are a lot of other social consequences.

Might not bring out the intended point or focus of the 'well-intended' answer ... so comparing it to examples from different continents makes not much sense. PS: I'll be glad to upvote without this contentious part. My view though

@semmyk-research I can say in other ways, too, that the values of Germany/ the EU are different from other countries, but it will make people more upset.


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Is it more probable to get into a college for master/bachelor, if we previously studied in that country for lower level?
Suppose I am an international student living in country Y and I apply to university Z in a european country/developed asian country Q. Would my chance for admission into Z, if applied, depend substansially  on whether I did my previous schooling in Q or not? Would this be different for different levels like Bachelors and Masters?
Eg:
I do my Bachelors in India and try for Masters in America
Vs,
I do my Bachelors in America and then try for Masters in America again.
Of course, I do agree for some countries there is additional process. Eg: Germany an Indian student has to do one more year of highschool before university in undergraduate but that is not important for me here. I only care about the raw rates.
N.B: By competitive college I mean a place where there is a bit of competition for seats. For places with no seat caps then theoritically none of this matters.

There is a difference. I would not call it substantial, but it is still there.
One of the difficulties of a admissions committee is that the members are much more familiar with the universities close by; maybe one of the members studied there, worked there, collaborated with someone from there, had students from that university, etc. They have an idea about that university, and what a degree from that university is worth. There is no such personal relationship with many universities further away, making it harder to evaluate those universities.
Another difficulty many applicants have is what is expected from letters of recommendation differs from country to country and culture to culture. This makes it very difficult to evaluate some of those letters that come from far away.
Both problems can be dealt with, and many committees are aware of them and do their best, but it is a friction that international students have and local applicants don't.

First, such data would be difficult to obtain, but, also, more difficult to interpret. And, since you added "substantially", then I'll guess "no", or it would be a well-known effect.
But, more to the point, if your question is actually looking for advice on what you should do to increase your likelihood of acceptance to a competitive college, I suggest you look elsewhere, such as gaining all possible knowledge and skill in the field(s) of interest and trying to have something tangible to show for that, or even intangible in the goodwill of your current instructors.
The one way in which it might be advantageous to study in Q is that an application might be easier to analyze, since readers are more familiar with that educational system. But if it comes at the cost of having less time to "impress" potential letter writers, then it could easily turn in to a negative. That would be especially true in the US, where letters carry a lot of weight.
The problem is that there are too many possible factors affecting admissions (at any level) to pick out one and depend on it to get you over the line. And there is so much "noise" in any such data set as to be probably meaningless and almost certainly meaningless to an individual case. Gaming "at the margins" isn't going to be helpful.

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What are the necessary and recommended practices to cite a published picture of experimental result?
I want to make a direct comparison between my simulation result and a published picture of other people's experimental result.
There are a lot of morphological features of similarity, which are difficult to describe by words only, and it should be better to simultaneously put the two results in my paper instead of suggesting readers to find that cited picture themselves, so I want to make the comparison by putting their picture and my numerical result side-by-side.
Specifically,

The picture of their experimental result was an optical photograph in black and white, while my simulation result was colorized;
My target journal is different from that of the cited paper.

I did find a similar example for my reference and thus I kind of doubt that this is not a usual practice in paper writing. Could anybody suggest me what should do before I prepare such a figure and submit my paper? Thank you!

If the source is an open-access paper under a creative commons license, it's easy - copy the figure and attribute the source and license.
If not... most publishers have a system for this. The STM Association, which covers the majority of mainstream scientific publishers, has a set of guidelines for permission between its members, setting out what is reasonable to reprint, and importantly has a general reciprocal agreement that they will honour each others requests without charge. This covers both books and journals, broadly speaking.
The STM list has the appropriate links per publisher. Some have a blanket permission, others require a bit of paperwork. For example -

a figure copied from a Portland Press-published paper does not require permission to be reused;
a figure copied from a Royal Society of Chemistry published paper does require permission, but this permission will be automatically granted at no cost if you fill in the online form correctly.

You do not need to do this before submission (at least, not in the cases I've dealt with) - it comes after acceptance when you know where it will be published and you're sorting out the details.
In the majority of cases, because copyright is transferred to the publisher (or they are given a very broad license to authorise republication) you do not need to approach the author. However, you might want to anyway.
Firstly, it's polite, and I'm sure they'd be pleased to know you're publishing something building on their work. :-)
Secondly, and potentially more importantly, permission to republish doesn't mean that the publisher will send you the files. You might need to get hold of a copy of the master images rather than the version put out by the first journal, in which case you'll have to speak nicely to the original author and hope they can find them...

Thanks for your suggestion and guidance. I need to reuse a figure from an Elsevier-published paper. According to the STM list, Elsevier does not require permission to be reused. So I can copy it in my paper directly with proper citation? In any case, it is only necessary for me to contact the publisher other than the journal and the author?

@jsxs assuming your publisher is also an STM signatory, that should be fine - note that the citation should probably include a copyright note. when accepted, the publisher may ask you to confirm permissions for the figure, in which case you can always go through the RightsLink process outlined here - https://www.elsevier.com/about/our-business/policies/copyright/permissions - it's fairly painless if you remember to tick the right boxes.

You will need to contact both the corresponding author of the cited paper and the journal the paper is published in. The details surrounding what you can do with republished figures differs by the source journal's policies and licenses (see how PLOS has a CC BY license, for example). The key element is to secure written permission from people responsible for the original figure - the source journal will let you know know how to handle that.

This is true in some cases, like for Nature journals: https://www.nature.com/reprints/faqs.html - primarily because the publisher retains the copyright. Edited answer accordingly.

@DSVA, do you mean the publisher instead of the journal?

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text:
Who are the editors of the Proceedings of the Survey Research Methods Section?
I want to cite a paper published in the Proceedings of the Survey Research Methods Section. But I cannot find who the editors are/were or if there are any at all.

Why do you need to know who the editors are?  You only need the name of the authors when you cite a paper.

@JoelReyesNoche For some conferences, the conference participants can hand in there presented research as proceedings papers. They will be peer reviewed (and possibly rejected) and edited by the editors. So they have some kind of effort and if possible I would like to acknowledge them (like editors of a book).

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text:
Galley proofs for journal article - can I make statistical changes?
I have had a paper accepted to a good journal (Animal Ecology) and have just received the proofs for checking. However my supervisor has suddenly decided that we need to redo some of the statistics(!) and present the statistics in a different way. I know that you can't make lots of changes, but this won't be too many words, just some statistics. Is is possible at this stage or is it too late?

I am asking specifically about statistics in the paper rather than wordy changes.

For all the journals I am familiar with, this is a big no-no.
At the galley proof stage, your paper has already gone through peer review, and any substantial changes to the manuscript, especially in terms of its scientific content (such as the statistics you mentioned in your post), can be seen as an attempt to contravene the peer review process.
Galley proofs, taking the literal limited sense, should mostly be concerned with fixing differences that arise in the production process, where the publisher mistakenly changed the content/intent of your article through misprints, omissions, etc. Most journal would also not mind when you want to make stylistic/grammatical improvements (basically things that copy-editors should be able to sign-off on). But the science should stay fixed once the peer-review stage is over.
However, you can try to contact the editor to see what your options are. Depending on the publisher and the editor, it could be anything from the editorial board approving your proposed change (because they have the expertise to assess that the change does not significantly change the scientific content of the article), them rejecting your proposal, or perhaps even a decision to send the paper out for a second round of peer review.


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Invitation to help writing and submitting papers -- how does this scam work?
I got several SPAM messages about conferences every week and know that most of them are scams, and can easily figure out what the scammers want (attend a weak conference, be an "estimated invited speaker", send credit card info, etc.) But today I got one that puzzled me -- a nice, educated offer that seems fishy (or am I getting paranoid)? I've added the text below.
I've found a site that matches the company description: https://www.journal.ac.cn/. It looks like a component of a research paper mill and contains the sentence "JDC, founded by academic elites from London, UK, is dedicated to serving the excellecnt academic journals to help them achieve ther dreams and targets, and help them to reach a higher level in the scientific publishing." [sic]
I am not going to fall for this, but am curious about the economics of the possible scam. They want to pay me to help with writing papers and submitting them to journals. Who pays for those services in an amount sufficient to pay me and those middlemen? If I needed help writing and publishing a paper I'd look to local help in my university or colleagues or colleagues of colleagues for free!
thanks!
Disclaimers: I've searched academia.stackexchange.com for similar topics and found none. I've redacted parts of the original message to protect the presumable innocent.

Dear Dr. [my full name which I don't use often],
I hope this email finds you well. This is [a generic name], a researcher from
Journal Developing Consulting Co.Ltd.
I am writing to ask whether you are interested in publication collaborations.
I came across your academic publications, and I was impressed with the quality of
your work. I believe that we share similar research interests, so I would like to
explore the possibility of collaborating with you on some upcoming publication needs.
Our team has been working on the publication of academic papers, and we are
looking for someone with your expertise to help suggest some high-impact journals
for publication and also follow the review process until acceptance. We understand
that this process can be time-consuming and demanding, and we would like to offer you
remuneration for your work and time on this. We believe that your input would be
invaluable in improving the quality of our publications and increasing their chances of
acceptance.
If you are interested in collaborating with us, please let me know, and we can
discuss the details further. Thank you for your time and consideration, and I look
forward to hearing back from you soon.
Best regards,
[a generic name]

Observation: The top-level domain is that of China, and the secondary that of academic. But ICP file (the serial number is at the bottom of the page "粤ICP备2021113231号-2" which you can lookup from https://beian.miit.gov.cn) at Chinese authority says the website belong to a commercial enterprise.

The way it is written screams "scam" to me. It's intentionally kept pretty vague, not telling you what this is actually about and the author tries to build trust by praising you into heaven... Either this is a creep, or - well - a scammer.

This is how I believe the actual scam works. There is some poor sod who has a low quality research paper and who wants it to appear in a reputable journal by unethical means if need be. Maybe they wrote it themselves, maybe it is also plagiarized somewhere or ChatGPT generated or something. It might be good enough for a paper-mill but a reputable journal will reject it without a second thought.
This is were you come in. You are a researcher who has published papers in reputable journals. You will be made a coauthor and your job will be to get this paper published in a reputable journal. Maybe your name alone suffices for that but that is unlikely. More likely you would have to do some real research and write a real paper and then get it published in a reputable journal.
How much work you have to do there is not really of interest to them, what counts is that the name of your collaborator appears as an author in a paper in a reputable journal. That is what you get paid for.

Makes sense. I've been talking to a colleague that told me he got some messages about "buying" rights to be named coauthor, with different price tags for being 1st, 2nd, and 3rd coauthor. And there is this: https://english.elpais.com/science-tech/2023-06-04/a-researcher-who-publishes-a-study-every-two-days-reveals-the-darker-side-of-science.html

@RafaelSantos There's also the possibility that the papers would be genuine, but the authors /knew/ that their English was weak: unlike whoever wrote the invitation you received.

Who pays for those services in an amount sufficient to pay me and those middlemen?

Oh, a lot, lot of people!
Only a fraction of the people who can benefit from publication credit actually have the want, means, or ability to conduct research. Examples include:

Industry workers who want to increase their profile among peers or increase their chances of getting a job.

High school students looking for an edge in college admissions. There is an industry of middlemen with contacts within university faculty who negotiate inclusion of high school students as co-authors for cash. See this from ProPublica:  The Newest College Admissions Ploy: Paying to Make Your Teen a “Peer-Reviewed” Author

Professors at teaching institutions which require that professors publish, but the institutions have no capacity of evaluating the legitimacy of the publications, and provide zero support for the professor to do any kind of research.

Researchers in countries whose government use a formulatic approach to salary and/or promotion, while the same governments provide zero support to accomplish actual research.

And of course, the lazy, and the incompetent. None of these people have any incentive to access the free resources you mention.

If this is a scam or not, I'd look beyond the person offering to be the intermediary. In my view, the person purchasing the publication is the actual scammer, scamming the public (via increased salary from public sources), their institutions, their peers, etc. There's a similar discussion going on regarding so-called "predatory journals." When talking about predatory journals, who is the actual scammer? The person submitting junk to a journal who will publish anything for money, to then use the publication record to defraud their employer? Or is it the facilitator of the scam, i.e. the publisher?
One last note about the misspellings on the email you received. I've heard some convincing arguments that misspellings on email scams are not a bug, but a feature. The idea is that the scammer is not looking for potential marks among sophisticated readers, but among those that either cannot see the misspelled words or don't care. So when you are turned off by the misspellings, you are in fact filtering yourself out and are not going to waste the time of the scammer. The only people who contact the scammer are thus self-selected pre-screened as easy marks.

In the interest of not perpetuating rumors, I researched scammer grammar and was not able to find any evidence that scammers make English mistakes on purpose. They're just non-native speakers.

https://security.stackexchange.com/questions/96121/why-do-phishing-emails-have-spelling-and-grammar-mistakes

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Can i be a corresponding author?
I am a PhD student now and i am willing to publish my masters degree research work, but the supervisor is refusing to publish for many reasons concerned him not the quality of my research.
There is no other way just to remove his name.
the question can i be a corresponding author ?
Thanks.

Your question is not about being a corresponding author but rather whether you could remove your supervisor from your paper. These are two VERY different aspects!

voting to close since the answer depends on those 'so many reasons' your supervisor is concerned about and your personal condition.

If the work is yours and yours alone then you can do with it what you like.
However, a better question might be whether it would be wise to cut out your advisor. If you want to build a future for yourself in academia you should try to build bridges to your advisor, not blow them up. This is a political issue, not necessarily one of fairness.
But, your advisor should have more experience in these things than you do, so their opinion might actually be valid.
Also, if your work isn't yours alone, but was done in concert with others, including your advisor, then you actually need to come to a joint understanding in order to publish it without breaking ethical norms.
The answer to can I do this and should I do this aren't necessarily the same. Take a long view before you decide.

There's nothing stopping you being the corresponding author on a submitted paper - I was several times during my PhD. But you can't submit a paper with your supervisor as a co-author without his agreement.
In general, it's worth listening to your supervisor. If he doesn't think the work should be submitted for publication there's probably a reason why. You don't specify what reason he's given you - that might be helpful to people trying to answer your question.


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In which ways are German university maths courses difficult?
It is established that the pass rates in Germany university courses are low. Typically people would say as explanation of how this happens, that the universities increase the difficulty of their courses or that there is not enough student support by teachers.
Disregarding support from teachers, in which way exactly are courses in German universities difficult for student? How do the teachers raise the course difficulty?
I am particularly interested in the case of bachelors in mathematics.

What you you mean by "mathematics"? Formal studies in math (e.g., leading to a B.Sc. in math), or "math for X", like "math for business majors"? If the former, my understanding is that in the US, courses will rarely have proofs and much more rote application of differentiation, integration or linear algebra formulas - whereas math in Germany is almost nothing but proofs. Your very first session might be devoted to the construction of the rationals from the integers through equivalence relations. The effect of a "salutary shock" is probably entirely intended.

I understand that this is the case @StephanKolassa

Possibly mathematics has a natural level of difficulty, or as I sometimes call it, "brutal honesty". Arguably the real challenge is how the U.S. system makes it so easy to pass. The mount-Everest amount of institutional effort at my college that's gone into trying to simplify tests, merge classes, remove requirements, provide corequisite supports, etc., is really jaw-dropping. At the high schools I'm told it's come down to flat-out administrative fiat that you must pass students even if they do literally nothing.

Related: Why are low pass rates (below 50%) for exams considered acceptable in Germany?

Because they are in German!

This can only be answered by comparison.
There are a number of differences in the teaching cultures of the USA and continental Europe. I have taught classes in both countries.

You pay virtually no tuition fees at German universities in comparison to US universities, even as a foreigner. Whereas in the US you are a paying customer and you essentially buy your degree, in Germany you are supposed to prove that you are worthy of getting the degree.

American universities focus on 'teaching' in the sense of the teacher feeding knowledge into students. Students have a rather passive attitude. At German universities the focus is on 'learning', meaning the students play the active role.

The general German attitude is that 'everyone gets a shot' at passing but they make it insanely difficult in order to filter out people.

At American colleges, students take a semester-long class where they practice mathematical reasoning. For example, they will talk one month about mathematical induction. At German universities, the teacher will talk about it for ten minutes, you get a few exercises, and then you are supposed to get it.

The focus at German universities is on axiomatic build up, even in classes for non-mathematicians, whereas American universities never do those foundations.

Typically, science classes are a few years ahead of their American counterparts.

German students finish high school much later. Much of what Americans do in their first few college years is considered high school material in Germany.

In addition to more material expected when entering university, the pace is much higher. What is graduate class material in the US will be undergraduate at many European universities. It is generally expected that students complement their studies with additional reading.

Depending on the place, 50% of students will fail at the exam, and that's the desired outcome.

If you want to get a direct impression in comparison to US universities, I'd recommend taking a look at, say, Koenigsberger's "Analysis I" book. On the other hand, the linear algebra books by Serge Lang have the reputation of being difficult (so Americans told me) but are considered accessible reading by most German students.

Valid points, but, I feel this still doesn't answer exactly "how the difficulty is raised". It answers to me, more of "what is the reasoning behind the raised difficulty"

The fourth and the fifth bullet points are the actual answer, the rest is quite correct, but addresses why math in Germany is harder rather than the original question how. Perhaps you want to edit your answer to expand on these two points, and deemphasize the rest?

I have added a few more points. However, I think it's very important to understand the broader economic/cultural/social context rather than a few examples. If you understand the former, then everything else follows.

@TrystwithFreedom: thinking about that, German math classes tend to emphasize broader understanding and will leave examples to you to figure out.

@TrystwithFreedom: Just a small note, but I think the wording "how the difficulty is raised" is a bit misleading, since it seems to presume that there were somekind of natural "ground state" with low difficulty, from which German universities or teachers chose to deviate for some reason by "raising the difficulty". From the opposite perspective one could just as well ask (and I would just as well object this wording) "how is the difficulty in the US lowered?"

The general German attitude is that 'everyone gets a shot' at passing but they make it insanely difficult in order to filter out people. – I find “insanely difficult” exaggerated. If everybody gets a shot, those with bad aim will miss that shot, and be filtered out. Of course, individual courses may be insanely difficult due to bad teaching or exam design, but in general, this is not required for filtering and also not done in my experience.

the linear algebra book's by Serge Lang have the reputation of being difficult (so Americans told me) -- Perhaps you meant Lang's Algebra rather than Lang's Linear Algebra? His "Algebra" book definitely has a reputation of being difficult (I had a 2-semester graduate algebra sequence in the late 1970s that supposedly used Lang's text), but his "Linear Algebra" book (which I'm less familiar with) seems similar to other (once) standard upper undergraduate level LA texts (e.g. Halmos, Hoffman/Kunze, etc.).

A close friend of Lang's told me over dinner once: "We knew his books were terrible, but we all loved him anyway".

@DaveLRenfro thank you for clarification. I actually find his Algebra book still a good and accessible book in comparison to many continental European algebra books, which seem to compete for being a torture to read.

his Algebra book still a good and accessible book in comparison -- I find that Lang tends to use shorter and less complex sentences than many authors (in this sense, he is somewhat like how Asimov compares to most other popular science writers), which makes for more straightforward reading and probably works especially well for non-native English speakers. On the other hand, students who like a lot of motivational exposition and a stylistic/poetic literary style probably find his texts to be a bit terse and bland. (continued)

The main problem with his Algebra text for myself and my classmates (late 1970s) was the high mathematical maturity level required at the very beginning (Chapter I on groups), although as I was told by faculty at the time, his book was specifically chosen for this reason -- first year graduate students were expected to rise to "Lang's level" of maturity by the end of the first semester of the 2-semester graduate algebra sequence. Incidentally, I especially like Lang's "Calculus of Several Variables" text (e.g. see 2nd paragraph here).

To add to Ambicion's and Maarten Buis' excellent answers, here are my two-cents based on getting a doctorate in Mathematics in Germany and then teaching in the US. From what I can tell, things in the US have not changed enough in Mathematics (I now teach in CS).
Beginning Mathematics in Germany was more abstract and used the axiomatic method, whereas for example Calculus in the US is aimed at natural scientists and especially engineers (at least at my school, the engineering school drives what is to be covered in Calculus). The equivalent class in Germany is Analysis. In the US, students are taught to calculate integrals and derivatives so that they can later do Fourier analysis and similar transforms, even though most of the students do never use them. In Germany, we were taught how to derive analysis from first principles and how to prove the important theorems. In the US, the quotient rule of differentiation is not often proven, whereas it is standard in Germany. In the US, students learn how to prove theorems maybe in the last semester of their sophomore (second) year and usually later. In my school, this is done with Discrete Mathematics and with Linear Algebra.
From what I can see what is happening in Germany right now, the engineering schools will teach their own Ingenieurmathematik classes as some did in my years, just after the Romans left the Rhineland.
So, even with the change in orientation towards the new B.S. degrees, I would still assume that beginners classes in Mathematics have a different goal than beginners classes in the US.
I am just supporting here what Maarten Buis and Ambicion wrote, even if I am not repeating their arguments. There are also great observations in the comments. This is a very interesting question that you are posing, worthy of a much deeper investigation.

I studied math in both the US and Germany (in the US at an expensive private university; i.e., not somewhere where the students need remedial math classes). In my experience, the programs are about equally rigorous. I would not say that the material in German courses is particularly hard, although it's possible that the pace is faster; in Germany not all the homework or test questions will be covered in class, and you have to supplement with your own reading.
The biggest difference is probably that in most (all?) German universities, your grade is based completely on a single final exam, whereas at US universities, a large proportion is based on homework. This means that in the US, a poor student can scrape by by just copying from a classmate. In my experience it was also much more common at German universities for students to show up unprepared for the final exam. There are multiple reasons for this; for example, Germany makes it fairly simple to repeat a failed exam, whereas at a US university, if you failed the final you would have to repeat the entire course. No doubt, however, this also contributes to the low pass rates.

You can raise the difficulty of a course by:

covering more material
covering more complex material
covering the same material but accepting fewer failures
any combination of the above

Comparing US and German courses in this respect is rather complex as the mathematics education in secondary education in the US is notoriously bad. So what is complex mathematics for a first year student in the US is something the German students learned in the 3rd or 4th year of Gymnasium.

Hmm, while I undersrand the general point of the answer, I'm wondering whether the last paragraph isn't quite an exaggeration. In most federal states in Germany 3rd or 4th year of Gymnasium means that students are about 13 to 14 years old. In those grades I learnt for instance: basic algebraic manipulations of variables, binomial formulas for (a+b)^2 and the like, linear equations in one variable, and things if similar difficulty. I find it difficult to believe that this counts as complex mathematics for first year students at most colleges in the US.

Don't underestimate what students find hard, some have trouble with fractions or that multiplication comes before addition...

@JochenGlueck: https://hechingerreport.org/for-community-college-students-who-struggle-with-arithmetic-some-solutions/

@DanielR.Collins and MaartinBuis: After reading Maarten's response and the first paragraph of the article linked by Daniel, my first impulse was to point out some nitpicky reasons why we might be comparing somewhat different things here. But then I read the rest of the article and now I have no idea what to reply. Maybe you're just right that I'm overly optimistic (I guess there's a considerable bias in Germany to always think about those few fancy elite universities when tertiary education in the US is mentioned). Shiver.

While there is some truth in the last paragraph (e.g. basic Calculus is a compulsory part of school education (for the type required qualify for university) in Germany), there is still a difference between what the students are supposed to know and what they actually do. I've seen more than one German first year student struggle with compound fractions...

Comparing community college (CC) in the US to college in Germany is woefully confused. In US CC, the vast and overwhelming number students are admitted. There are not placement tests or much in the way of excluding criteria - in most cases there is nearly nothing short of failing out of college already that can disqualify admittance. One might be able to make a meaningful comparison comparing equally selective US institutions.  I do not know of meaningful comparisons to CC in Germany. @DanielR.Collins

Universities in Germany generally do not select either, other than having finished gymnasium.

@RegressForward: The entire point of this rather long series of questions by the OP is they're trying to wrap their head around Germany's apparent lack of excluding criteria to enter college programs.

@Maartin, as you point out Gymnasium is already selective, not every child is required or allowed to attend (looks like about 28% of "precollegiate students"). If you still must pass the Abitur, in 2010 only about 50% of students passed, so at least historically it was a limiter.

@RegressForward Historically the Abitur has been a real barrier. Now not so much. In the cohort of 25-30 year olds in 2019 (the most recent data I could find on quick notice) 54% had Abitur. On top of that there are various other ways of attaining a "Hochschulberechtigung"


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Can we put some documents which are not listed as required documents for jobs
I am going to apply for non-tenure tack academic position and I have already prepared all documents. They did not list Cover Letter as a required document. I would like to know whether it is necessary or not to put this document in my application?

A cover letter is probably fine, provided that the application system will accept it. Some online systems can be strict about what they will accept. If they want a SoP (Statement of Purpose), they probably expect to see there what you might otherwise put in a cover letter.
But avoid including a lot of unasked for documents. The institution knows what it wants to see and wants all applications to be similar in structure just to ease the work of evaluation.
In required documents you can sometimes point to the existence of other things that people might want to see if you are seriously under consideration. But wait until you are asked to send those extra things.

If in doubt, ask.
Buffy's advice is good, but I have previously benefited from sending a testimonial when such things weren't requested. I wouldn't include extra documents unsolicited, but if there are other things that you would like to include, contact the people handling the recruitment and ask if it's OK.


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Should I reply or reply to all in the case of recieving a job offer?
I have received an offer from a university and I want to accept that. In their email they have sent a cc email to another person who is probably the head of HR. In my response, I want to know whether I reply to the sender or reply to all?

In such cases, it is clear that those people are cc-ed to be kept in the loop. So yes, reply to everyone.
(Unless you are very sure they have been cc-ed for some other reason, related to the making of the offer, but not it's acceptance, which is hard to imagine, and would require knowledge of the inner workings of the university.)

Reply-all. The others in the cc are being cc-ed because they are involved in the hiring process and need to know what you decide for their work.
Having said that, the cost of hitting reply instead of reply-all in this scenario is probably basically nothing except someone maybe thinking "I wonder why they didn't hit reply-all" for a few minutes; what will almost certainly happen is that the person who you sent the response to will immediately forward it to everyone else.
My main point is, don't over think it.


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About approval of grant of potential mentor
About three months ago I sent an email to ask a professor about postdoc position under her supervision. Her feedback on my cv was positive and she told me that she intend to apply for grant this year and consider me as a potential postdoc. She also mentioned that she keep me informed if the appîication for grant be successful.  Indeed, she told me she will inform me, but because of the fact that professors are busy people,  I do not know she remember me or not?
 I do not know whether I send another email to ask her about the status of availability of grant or not?  If so, what should be a proper context of email to ask that.

It is perfectly reasonable for you to politely seek an update in these circumstances. She likely has not heard back about the grant, even if she submitted it the day that she emailed you (three months is not very long in a grant funding cycle), but she will have a clearer picture of what her plans are with regard to the application and, perhaps, with regards to you. It is a very busy time of year right now with the start of term (if she is in the northern hemisphere) so perhaps wait until the first week of October, but a short, to the point, and very polite email would be appropriate.

Definitely follow her and her team on the various digital networks that they may be on. Most teams have Twitter and university groups.
Figure out when the grant rounds are decided and published. Most national grants will have public websites etc. Private grant institutions may also have ways to follow them.
But what is more important for you is to know when your usual post doc dates and times are. Her grant may be after that time which may limit your choices. Keeping all the factors in mind is an important strategy.


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About the name of suggested reveiwer
I am going to submit a short math paper to a journal. During the process of submission I am asked to suggest the Editor \ Reviewers. In this respect, can I write the name of my co-advisor of my Ph.D as a potential reviewer? Need to say, we have a joint paper with my co-advisor.

How many years (weeks) have passed since your PhD?

Recent joint papers are one of the first examples of conflict of interest most journals mention, see for example here and here. Being your advisor is also explicitly mentioned as a conflict. I would avoid suggesting this person as a potential reviewer, this will at the very least raise eyebrows unless you have a very convincing reason.

If this co-advisor is

not involved in the work leading to the current paper
is knowledgable in the area of the paper

then it would be fine to suggest the coadvisor as a reviewer.
For a more senior researcher it is quite common to personally know essentially everyone who is qualified to review their papers and to have co-published with a lot of them. Most of their papers will be reviewed by people they know.


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Replying to potential professor about my position
I sent an email to  Professor A sometimes ago and he has recently showed his interest in my work and replied my email. He is asking about what is my research plan for my future. At the moment I am a postdoc in another country and I am looking for a postdoc position with respect to my research goal. In this respect, I have recently  applied for a postdoc position such that the result of accepted candidate will be announced soon (probably next week). My question is: Is it necessary to write about this details ( my recent application for postdoc position) in my replying email to Professor A?

You could easily reply now and say you are looking for a position and have made some applications. Just start the conversation. It may be that by the time you get a reply from him you will know more about your other prospects.
Perhaps the first mail need not be very detailed, but you could ask about the possibility of working with him if you haven't done that already.
It might be valuable to keep in touch even if you wind up with the other position. Nothing is forever and a circle of collaborators is valuable.
And you might get a reply around the time that you hear about the other position and can make some decisions or follow up more seriously.


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postdoc with professor that I had email exchanging for PhD
3 years before I exchanged email with a professor for Ph.D program. He sent me several links including the process of his university for PhD and some useful links, in the meanwhile I also contacted to another professor in another country. I selected the second option to continue my PhD. Now I completed my PhD. Is it ethical to send email and ask the first professor for postdoc position?

Yes, of course. Your earlier decision doesn't reflect at all on either of you as you had a variety of criteria for choosing. You don't need to defend that decision in any way. The prof in question was interested in you at one time and may still be interested.
The professors needs may have changed, of course. But if you apply you an even remind him/her of your earlier exchange, providing thanks for the earlier guidance. Of course, make sure that you have some knowledge of the potential position and the work of the professor and how you can contribute to it effectively.
There is no ethical issue and while there might be cultural issues in a few places, one hopes that those are minor in the modern world.


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What is the meaning of pre-doctoral program?
I do not know the exact meaning of pre-doctoral?
Can someone be a predoctoral in university X and then goes to university Y to start Ph.D?

What it is exactly will vary between institutions, but often includes things like:
Library use - services for researchers etc
Research methods - a reminder / review of research practices - some are coming back after a period away...
It could also include some courses that are relevant for some while not others ie advanced calculus if that is needed and the student did not take it in the studies they have done already.
So, it may or may not be identical, but the purpose is the same. Some institutions will have this as a prior requirement others run it in parallel during the first 6 months...

In some parts of the world, this is the term used for a PhD program.
Before you obtain your doctorate (i.e. PhD), you are a pre-doctoral fellow or a doctoral candidate. After you have obtained it, you may become a post-doctoral fellow.
Example: http://www.ral.uni-leipzig.de/en/home/postdocs/pre-doc-award/

In other parts of the world, "predoctoral" may refer to the period before a student enrolls in a PhD programme.

On a related note, the term "PhD" is much abused these days with students who have not yet obtained a PhD being referred to as "PhDs". This is quite inaccurate as they have not yet obtained the degree and are thus not "doctors". They are a "PhD students", i.e. studying towards obtaining a doctorate.

Actually, in the U.S., in mathematics, it is quite popular current usage to say "start a Ph.D.".

@paulgarrett Fair enough, removed that bit.


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Do I have to do a Masters and a PhD thesis?
I am currently perusing my masters degree in engineering, and would like to continue that with a PhD, and it was my understanding that I needed a thesis for my masters in order to get into the PhD program. Is this true? I'm beginning to reach out to professors to see if they will take me on, and when I mentioned a masters thesis to one of them, he said it would be better just to take the class requirements for a regular masters degree, but I could start looking at my PhD thesis now. Does this sound right? Thanks for your input!

It depends largely on the country and institution.  Some PhD programs in engineering require a Master's with a dissertation.  Other programs are content with a course-work-only Master's.  Your best bet is to find a person to work with at the department of the PhD program you want to enter (which it sounds like you have already done) and follow the advice of that person.

My program didn't even require the Master's. You could pick one up based on coursework only along the way for a small fee, but it was mostly there as a bailout option for people who wanted out of the program at that point. I didn't pick it up.

Indeed. In some countries and institutions, a Master's is viewed as the "first 2 years of the PhD program", with an option to exit after year 2 with just the Master's or to continue to complete the PhD.  In other countries (such as Canada) it is often a pre-requisite to apply to a PhD program (though it still varies by institution and some allow direct admission from undergrad in certain circumstances).


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My master thesis supervisor wants me to continue as his PhD student, but he has no funds at the moment. Any advice?
I am currently working on my master thesis in physics and mathematics and will finish within a few months. My supervisor told me he would like to continue with my thesis' research subject and asked me if I wanted to be a PhD student in his group. However, he doesn't have any funds at the moment for hiring another PhD student, although his current PhD students are all almost finished.
He is going to look around and obviously will continue submitting proposals for grants. But unless we are very lucky, there won't be a grant within a reasonable time. He offered to help me get a PhD somewhere else and write a good letter of recommendation. I think the chances are good to obtain a PhD position somewhere else. However, I would like to find a way to do a PhD with my current supervisor.
Does anyone have any ideas how to get funding or something else I could do? This is at a university in The Netherlands and a PhD is considered as a job here. Funding is almost never arranged by the PhD student his/herself.

Get a funded position at all costs, even if it means leaving your current supervisor. You can still continue to collaborate even if you are not his student.

Being in the state of financial hardship seem to drop IQ around 13 points. You don't want that. Reference: https://science.sciencemag.org/content/341/6149/976

Yes, I am definitely not considering doing this PhD without funds. That's also not really an option in my country, as far as I know.

@astronat, if you add more to that comment, it could be an answer. It's almost more than a comment already, as it gives relevant advice.

There are -mainly- two options in the Netherlands to arrange your own funding.
Get a talent scholarship from NWO. See here: https://www.nwo.nl/en/research-and-results/programmes/magw/research-talent/index.html
Or, as you are in beta science a very good option, is to find a company that will hire you and will allow you to do the phd externally. This allows you to gain some work experience while doing the phd. You will take longer, but you will stay connected to practice.
By the way, in my opinion, to much of this 'yeah i would love to but i dont have funding' is coming from professors. If they really want you, they should only offer you a funded position. But that's from someone who left academia :)

If you are not starting as a funded student then you should assume that you’ll have no funding for the entire duration. Based on that assumption, can you somehow afford 1) tuition 2) living costs 3) auxiliary costs (social, personal, etc) for the duration of the PhD? And, if you cannot, are you willing to take on thousands (tens of thousands?) worth of debt to try and get that PhD?
If you cannot get funding, you may have to find a job to support yourself, but then of course, your time will be divided.
If you are not willing to find a part time job or you are not willing to take on a lot of debt, then you should not be doing your PhD with somebody who is unable to pay you.

Thanks! I will definitely not do a PhD without funding, that is not an option. My question was mainly how I could obtain funding (or help my supervisor obtain funding).

Simply by applying to funding agencies. You'll just have to do the leg work to identify which funding agencies you can contact. However, your professor probably already knows which funding sources you can or cannot tap, so when he says that funding is very unlikely, he's probably right.

PhD candidates in the Netherlands are not students and do not pay tuition.

@mmeent Even if they do not pay tuition, my point still stands: Can OP afford all expenses on their own without any source of income from research? Most likely not.

Even if you masters supervisor had funding, you should apply for multiple PhD positions at multiple universities.  Accept the best offer you receive.
In physics, I would not recommend an unfunded PhD to anyone who is not already wealthy.