Why we define supermum of empty set to be $-\infty$ contradiction?
1307
Infimum and supremum of the empty set
113790
$\overline{B_1(0)}$ is not weakly* sequentially compact in $(l^\infty)$'
114786
Question about Infimum. (conclusion about intersection)
146560
Is there any uncountably infinite set that does not generate the reals?
103383
Let $\{K_i\}_{i=1}^{\infty}$ a decreasing sequence of compact and non-empty sets on $\mathbb{R}^n.$ Then $\cap_{i = 1}^{\infty} K_i \neq \emptyset.$
110677
How is an empty set truly "empty"?
107842
Behaviour of ($\overline{a}_n)_{n=1}^{\infty}$ and ($\underline{a}_n)_{n=1}^{\infty}$
102585
Why is $L^{\infty}$ not separable?
23883
$\infty = -1 $ paradox
118573
Why is the Axiom of Infinity necessary?
59275
If $X$ is an infinite set, then $X$ with the discrete topology is not compact
65655
Give examples showing why $0\cdot \infty$, $\infty/\infty$, and $0/0$ are meaningless
126633
Is a contradiction enough to prove a set equality to $\varnothing$?
27107
intersection of the empty set and vacuous truth
27153
Definition of convergence of $\sum_{i=-\infty}^\infty a_i$
55619
What does $\bigcup_{i=0}^{\infty}[i, i+2]$ mean?
117561
A set is infinite iff there is a one-to-one correspondent with one of its proper subsets?