Metamath Proof Explorer


Theorem bnj1299

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

Ref Expression
Hypothesis bnj1299.1 φ x A ψ χ
Assertion bnj1299 φ x A ψ

Proof

Step Hyp Ref Expression
1 bnj1299.1 φ x A ψ χ
2 bnj1239 x A ψ χ x A ψ
3 1 2 syl φ x A ψ