Different arrows in set theory: $\rightarrow$ and $\mapsto$
142873
What does the function f: x ↦ y mean?
96025
Showing there is only one isomorphism between well ordered sets using transfinite induction
132868
Bijection between an infinite set and its union of a countably infinite set
95373
Additive set function on a semiring of sets
5639
No \xrightrightarrow[a]{b}?
89167
Cardinality of equivalence relations in $\mathbb{N}$
98518
Cardinality of equivalence relations on N
25260
Extension of a morphism $k^*\rightarrow X$ to $\mathbb{P}^1\rightarrow \overline{X}$
29755
Power set equivalency of Axiom of Choice
62687
Proving Cardinality of Cosets in Abstract Algebra
151521
Set Theory: Tree Property
81509
The cardinality of a countable union of countable sets, without the axiom of choice
62936
Proving equivalencies of two versions of the Axiom of Choice
14711
set theoretic function, products of sets (product versus Cartesian product)
105815
Does proving (second countable) $\Rightarrow$ (Lindelöf) require the axiom of choice?
120252
Equivalences of bounded sets definitions
46875
The identity morphism in $\mathbf{Set}$ is the identity function