Hilbert's sixth problem (current answers neglect the fact that $C_{U} \subseteq U $ )
25341
Does Gödel preclude a workable ToE?
137707
How to prove that $(A\cup B) \cap C \subseteq A\cup (B\cap C)$
33338
Problem on $\operatorname{Hom}(\mathbb Z_6,R^*\oplus C^*)$
94958
Prob. 6 (d), Chap. 1, in Baby Rudin, 3rd ed: How to complete this proof?
35115
Questions on how to prove that a set of connectives is NOT functionally complete
73869
$\mathcal{C}_1 \subseteq \mathcal{C}_2 \implies \sigma( \mathcal{C}_1) \subseteq \sigma( \mathcal{C}_2) $
145094
Is my basis for $U=\{p \in \mathcal P_4(\mathbb R) \mid p(6)=0\}$ correct?
87940
Question about bilinear form on Hilbert space
18125
Counterexamples to the converse to Lagrange's Theorem different from $A_{4}$.
102168
Prove that there exists disjoint open subsets $U,V$ of $X$ such that $x \in U$ and $B \subseteq V$.
130458
Why Godel's theorem influences Hilbert's programme?
27899
Can we prove the existence of $A\cup B$ without the union axiom?
139334
Determining the existence or non-existence of Non Trivial Ideals of $L(V)$
113152
Prove Principal Ideal Domain from Bezout's condition, and terminating divisibility chain
141318
$\subset$ vs $\subseteq$ when *not* referring to strict inclusion
63516
$C^1[0,1]$ is not complete with respect to sup norm
61710
Proof of Cauchy-Schwarz inequality - Why select s so that so that $||x-sy||$ would be minimized?