Metamath Proof Explorer


Theorem bnj1232

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

Ref Expression
Hypothesis bnj1232.1 ( 𝜑 ↔ ( 𝜓𝜒𝜃𝜏 ) )
Assertion bnj1232 ( 𝜑𝜓 )

Proof

Step Hyp Ref Expression
1 bnj1232.1 ( 𝜑 ↔ ( 𝜓𝜒𝜃𝜏 ) )
2 bnj642 ( ( 𝜓𝜒𝜃𝜏 ) → 𝜓 )
3 1 2 sylbi ( 𝜑𝜓 )