Metamath Proof Explorer


Theorem bnj1351

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

Ref Expression
Hypothesis bnj1351.1 φ x φ
Assertion bnj1351 φ ψ x φ ψ

Proof

Step Hyp Ref Expression
1 bnj1351.1 φ x φ
2 ax-5 ψ x ψ
3 1 2 hban φ ψ x φ ψ