Axiom of infinity and empty set
31212
The existence of the empty set is an axiom of ZFC or not?
74440
How does the axiom of regularity forbid self containing sets?
117561
A set is infinite iff there is a one-to-one correspondent with one of its proper subsets?
14972
Cardinality of Vitali sets: countably or uncountably infinite?
136755
Direct proof of empty set being subset of every set
66301
The cardinality of the set of countably infinite subsets of an infinite set
65768
What is the cardinality of the set of the empty set?
118573
Why is the Axiom of Infinity necessary?
31509
Is axiom of choice necessary for proving that every infinite set has a countably infinite subset?
157513
How can I prove that these sets are countable infinite?
18828
Base and empty set of a topology
7733
If A is infinite, does there have to exist a subset of A that is equivalent to A?
39020
Why is empty set an open set?
123498
Is "empty set" an element of a set?
88205
How can I define a topology on the empty set?
146560
Is there any uncountably infinite set that does not generate the reals?
24372
Infinite Set is Disjoint Union of Two Infinite Sets