How does one show that the set of all axiomatic proofs (in propositional logic) is countably infinite?
102113
Proof that the number of proofs is countably infinite
102202
The smallest infinity and the axiom of choice
125411
Infinite set always has a countably infinite subset
81509
The cardinality of a countable union of countable sets, without the axiom of choice
151295
Proving $|S \times \mathbb{N}|=|S|$ when $S$ is an infinite set
75007
How can I prove this relation between the elementary set theory and the elementary logic?
136006
Prove that any countable cartesian product of countable sets is countable
122947
What is the cardinality of the set of infinite cardinalities?
53025
Why the need of Axiom of Countable Choice?
132778
All distances are rational prove the set is countable
42095
Existence in ZF of a set with countable power set
48797
Proving Two Sets are Equal - Infinite Sets - Example
128437
How to prove that a finite set is countable
103769
The Cartesian product of a finite number of countable sets is countable
79490
Proving the set of points at which a function diverges to $\infty$ is countable
43268
How to prove that the set of rational numbers are countable?
44974
Infinite set and countable subsets