Metamath Proof Explorer


Theorem bnj1352

Description: First-order logic and set theory. (Contributed by Jonathan Ben-Naim, 3-Jun-2011) (New usage is discouraged.)

Ref Expression
Hypothesis bnj1352.1 ψ x ψ
Assertion bnj1352 φ ψ x φ ψ

Proof

Step Hyp Ref Expression
1 bnj1352.1 ψ x ψ
2 ax-5 φ x φ
3 2 1 hban φ ψ x φ ψ