What are the infinities p and t in set theory ??
108028
Is there a bijection between the reals and naturals?
77548
Given an arbitrary infinite set $S$, how to construct an injection $\mathbb{N} \to S$ with the Axiom of Choice?
148790
Basic question about proofs with the goal $\exists x P(x)$
9651
Cardinality of cartesian product of an infinite set with N
37183
Show that the set of all $x$ such that $x \in P$ and $x \notin Q$ exists
120712
Is there a way to define the "size" of an infinite set that takes into account "intuitive" differences between sets?
48797
Proving Two Sets are Equal - Infinite Sets - Example
139155
What does 2 to the power x mean in set theory
56637
In naive set theory ∅ = {∅} = {{∅}}?
109054
Given an infinite set of cardinality $X$, is there a chain in $\mathcal P(X)$ of the same cardinalty of $\mathcal P(X)$?
66398
Union of a finite set and a countably infinite set is countably infinite
12436
The cardinality of the set of all finite subsets of an infinite set
81943
How to finish proof that $T$ has an infinite model?
12539
Set Theory: Equivalency of Axiom of Choice and Choice Function
44974
Infinite set and countable subsets
2403
Can a countable set contain uncountably many infinite subsets such that the intersection of any two such distinct subsets is finite?
45878
Elementary Set Theory: Ordinals, Well Orderings and Isomorphisms