existence of transitive standard models of ZFC independent of existence of models of ZFC.
97156
ZFC + $\exists$ Standard model $\rightarrow$ Con(ZFC + $\exists \omega$-model)
102406
Why is it not true that if $\Phi \models \exists x \phi$ then there is a term $t$ with $\Phi \models \phi \frac{t}{x}$?
120529
Relations between diffeomorphism symmetry theories and invariant $SU(N), N \rightarrow \infty$ theories
118189
Proving the pairing axiom from the rest of ZF
35140
Existence of minimal $\sigma$-algebra and transfinite induction
19414
Uncountable subset with uncountable complement, without the Axiom of Choice
42095
Existence in ZF of a set with countable power set
84251
Show that $\Gamma \cup \{\neg \phi\}$ is satisfiable if and only if $\Gamma\not \models \phi$
1712
$ d_1,d_2\mid n\iff {\rm lcm}(d_1,d_2)\mid n\ $ [LCM Universal Property]
140335
Prove that the empty relation is Transitive, Symmetric but not Reflexive
55199
Number Theory in a Choice-less World
29744
Compactness and axiomatisability
113863
The non-existence of non-principal ultrafilters in ZF
30587
Uncountable well ordered set in $Z^-$ theory.
52949
If $aRb \land bRc$ never occurs, is a relation considered transitive?
73415
The reason why the existence of inaccessible cardinals cannot be proven in ZFC
44361
An automorphism that has no fixed points except for the identity and is its own inverse implies commutativity