Finite ratios between pairs of infinities
39878
How to divide aleph numbers
53593
Limits of sequences of sets
98518
Cardinality of equivalence relations on N
54262
When are infinities okay?
82207
Number of Pairs of Subsets
106455
intersection of infinite collection of finite sets?
122828
Proof that TREE(n) where n >= 3 is finite?
132537
Class of sets of a given infinite cardinality
77548
Given an arbitrary infinite set $S$, how to construct an injection $\mathbb{N} \to S$ with the Axiom of Choice?
68230
The cardinality of a countable union of sets with less than continuum cardinality
11849
Size of a union of two sets
66301
The cardinality of the set of countably infinite subsets of an infinite set
54761
Inverting the Cantor pairing function
39692
The length of an interval covered by an infinite family of open intervals
97064
Dense set in an infinite cofinite space
121366
Intervals and cardinality
128350
Number of non-decreasing functions between two finite sets