Metamath Proof Explorer


Theorem nvpss

Description: No class strictly includes the universal class. Dual of npss0 . (Contributed by BJ, 12-Jul-2026)

Ref Expression
Assertion nvpss ¬ V A

Proof

Step Hyp Ref Expression
1 ssv A V
2 ssnpss A V ¬ V A
3 1 2 ax-mp ¬ V A