Does definable imply recursively enumerable?
89749
Example of a not recursively enumerable set $A \subseteq \mathbb{N}$
42970
Proof of a proposition about recursion definition (Terence Tao's Analysis I)
133083
Injectivity and surjectivity of a recursive function
19414
Uncountable subset with uncountable complement, without the Axiom of Choice
79582
Nested Bounded Wildcard
99599
Uncountable and countable
129109
Is the set of polynomial with coefficients on $\mathbb{Q}$ enumerable?
128517
A recursive sequence is defined by...
34723
Proof of a limit for a recursively-defined sequence
61489
Is there a statement whose undecidability is undecidable?
105791
Does separability imply the Lindelöf property?
124961
Do Apex collections implement iterable?
119888
Is it possible to convert $\forall$ quantifiers to $\exists$ quantifiers without negation?
136081
Indecomposable limit ordinals
72007
What do finite, infinite, countable, not countable, countably infinite mean?
57071
Examples of Recursive functions
6535
Proof of for-all / there-exists "negation"?