Metamath Proof Explorer


Theorem kardfn

Description: The kard class is a function on the universe. This theorem depends on the Axiom of Regularity and the Axiom of Infinity, but it does not depend on the Axiom of Choice. (Contributed by BTernaryTau, 3-Jul-2026)

Ref Expression
Assertion kardfn Could not format assertion : No typesetting found for |- kard Fn _V with typecode |-

Proof

Step Hyp Ref Expression
1 scottex2 Scott y | y x V
2 df-kard Could not format kard = ( x e. _V |-> Scott { y | y ~~ x } ) : No typesetting found for |- kard = ( x e. _V |-> Scott { y | y ~~ x } ) with typecode |-
3 1 2 fnmpti Could not format kard Fn _V : No typesetting found for |- kard Fn _V with typecode |-