Metamath Proof Explorer


Theorem termcnex

Description: The class of all terminal categories is a proper class. Therefore both the class of all thin categories and the class of all categories are proper classes. Note that snnex is equivalent to snglV e/ V . (Contributed by Zhi Wang, 20-Oct-2025)

Ref Expression
Assertion termcnex Could not format assertion : No typesetting found for |- TermCat e/ _V with typecode |-

Proof

Step Hyp Ref Expression
1 snnex b | x b = x V
2 basrestermcfo Could not format ( Base |` TermCat ) : TermCat -onto-> { b | E. x b = { x } } : No typesetting found for |- ( Base |` TermCat ) : TermCat -onto-> { b | E. x b = { x } } with typecode |-
3 1 2 fonex Could not format TermCat e/ _V : No typesetting found for |- TermCat e/ _V with typecode |-