New posts in cardinals

Why do we classify infinities in so many symbols and ideas?

cardinals infinity ordinals

Is $\alpha < \beta \to 2^\alpha < 2^\beta$ provable in ZF+V=HOD?

set-theory cardinals

Is there a way to define the "size" of an infinite set that takes into account "intuitive" differences between sets?

set-theory cardinals

Cantor-Bernstein-like theorem: If $f\colon A\to B$ is injection and $g\colon A\to B$ is surjective, can we prove there is a bijection as well?

set-theory cardinals

Why the principle of counting does not match with our common sense

elementary-set-theory intuition cardinals

Show that an infinite set $C$ is equipotent to its cartesian product $C\times C$

elementary-set-theory cardinals

Which set is unwell-orderable?

elementary-set-theory cardinals axiom-of-choice ordinals

Cardinality of $\mathbb{R}$ and $\mathbb{R}^2$

elementary-set-theory cardinals

The cardinality of a countable union of countable sets, without the axiom of choice

set-theory cardinals axiom-of-choice ordinals

Godel's pairing function and proving c = c*c for aleph cardinals

set-theory cardinals ordinals

Cardinality != Density?

cardinals

Do $\omega^\omega=2^{\aleph_0}=\aleph_1$?

set-theory cardinals ordinals

Is there an infinite topological space with only countably many continuous maps to itself?

general-topology cardinals

There's non-Aleph transfinite cardinals without the axiom of choice?

set-theory cardinals axiom-of-choice

Proving that for infinite $\kappa$, $|[\kappa]^\lambda|=\kappa^\lambda$

set-theory cardinals

For any two sets $A,B$ , $|A|\leq|B|$ or $|B|\leq|A|$

set-theory cardinals axiom-of-choice

Cardinality of all cardinalities

set-theory cardinals

Is symmetric group on natural numbers countable?

group-theory elementary-set-theory cardinals

Why do the rationals, integers and naturals all have the same cardinality?

elementary-set-theory cardinals infinity

How to formulate continuum hypothesis without the axiom of choice?

set-theory cardinals axiom-of-choice