The negation of the continuum hypothesis as an axiom
44522
Subsets of the reals when the Continuum Hypothesis is assumed false
108922
Cardinality and infinite sets: naturals, integers, rationals, bijections
152685
Parallel postulate from Playfair's axiom
81509
The cardinality of a countable union of countable sets, without the axiom of choice
122184
De Morgan's laws in logic and set theory
60678
Does 'A countable infinite Cartesian product of countable sets is not necessarily countable' violate induction principle?
12539
Set Theory: Equivalency of Axiom of Choice and Choice Function
31392
Examples and Counterexamples of Relations which Satisfy Certain Properties
29744
Compactness and axiomatisability
3663
Finding counterexamples in elementary set theory.
126862
Confused about $x \notin x$ example in Axiom of Specification
40291
What's the point of the axiom of extensionality?
126713
Strong induction and vacuous truth
31212
The existence of the empty set is an axiom of ZFC or not?
9158
Proving that a propositional theory of any cardinality has an independent set of axioms
27899
Can we prove the existence of $A\cup B$ without the union axiom?
10255
Paradoxes without self-reference?