This is an inofficial mirror of http://metamath.tirix.org for personal testing of a visualizer extension only.

Metamath Proof Explorer

Theorem vprcOLD

Description: Obsolete proof of vprc , obsolete as of 1-May-2026. (Contributed by NM, 23-Aug-1993) (Proof modification is discouraged.) (New usage is discouraged.)

Ref Expression
Assertion vprcOLD ⊢ ¬ V ∈ V

Proof

Step Hyp Ref Expression
1 vnex ⊢ ¬ ∃ x x = V
2 isset ⊢ V ∈ V ↔ ∃ x x = V
3 1 2 mtbir ⊢ ¬ V ∈ V