Why $r \notin R^*$ if it is a prime?
69649
If an ideal contains the multiplicative identity, then it is the whole ring
115758
Remainder of division when $p$ is not prime
95111
Elementary proof for $\sqrt{p_{n+1}} \notin \mathbb{Q}(\sqrt{p_1}, \sqrt{p_2}, \ldots, \sqrt{p_n})$ where $p_i$ are different prime numbers.
101882
Does this polynomial evaluate to prime number whenever $x$ is a natural number?
71767
What is the difference between $\Bbb{R^n}\times\Bbb{R^m}$ and $\Bbb{R^{m+n}}$?
4105
Irreducible but not prime in $\mathbb{Z}[\sqrt{-5}] $
144622
Proof: If no prime less than or equal to $\sqrt{n}$ divides $n$, then $n$ is a prime
252
Why doesn't $0$ being a prime ideal in $\mathbb Z$ imply that $0$ is a prime number?
61899
Prove that the language $\{bin(p) \mid p\ \text{is prime}\}$ is not regular (prime numbers)
29572
Proof that $2^n-1$ does not always generate primes when primes are plugged in for $n$?
43282
Why do $n$ linearly independent vectors span $\mathbb{R}^{n}$?
2802
If $2^n+1$ is prime, why must $n$ be a power of $2$?
126862
Confused about $x \notin x$ example in Axiom of Specification
6702
Intuition for the prime number theorem
80658
Prove that the number $19\cdot8^n+17$ is not prime, $n\in\mathbb{Z}^+$
37315
not both $2^n-1,2^n+1$ can be prime.
95937
Why aren't all prime subfields equal to {0,1}?