Set Theory proof from "How to Prove It"
67709
Stuck with proof for $\forall A\forall B(\mathcal{P}(A)\cup\mathcal{P}(B)=\mathcal{P}(A\cup B)\rightarrow A\subseteq B \vee B\subseteq A)$
118189
Proving the pairing axiom from the rest of ZF
88982
Prove that for any two sets $A$ and $B$, $A\notin B$ or $B\notin A$
151295
Proving $|S \times \mathbb{N}|=|S|$ when $S$ is an infinite set
151852
How to prove $A \subset B \iff A \cup B = B$
122184
De Morgan's laws in logic and set theory
1821
Proving $f(C) \setminus f(D) \subseteq f(C \setminus D)$ and disproving equality
58186
Set theory proof, $\exists g(g\colon A\twoheadrightarrow C)$ or $\exists h(h\colon C\hookrightarrow B)$
62709
Functions that are sets of all function - proofs
100726
Prove that the set of powers of a set, $\{ A^n : n \in \mathbb{N} \}$ exists by using ZFC axioms (without replacement).
115606
Proofs involving $ (A\setminus B) \cup (A \cap B)$
50804
It seems obvious, but how to prove it formally?
19856
Prove that a subset of a separable set is itself separable
126015
Elementary number theory in sets
100399
A doubt with a part of a certain proof.
139247
Real Analysis - Prove a set is countable
148790
Basic question about proofs with the goal $\exists x P(x)$