Metamath Proof Explorer


Theorem imbi12d3

Description: Variant of imbi12d2 . (Contributed by Zhi Wang, 30-Aug-2024)

Ref Expression
Hypotheses imbi12d2.1 ( 𝜑 → ( 𝜓𝜒 ) )
imbi12d3.2 ( 𝜑 → ( ( 𝜓𝜒 ) → ( 𝜃𝜏 ) ) )
Assertion imbi12d3 ( 𝜑 → ( ( 𝜓𝜃 ) ↔ ( 𝜒𝜏 ) ) )

Proof

Step Hyp Ref Expression
1 imbi12d2.1 ( 𝜑 → ( 𝜓𝜒 ) )
2 imbi12d3.2 ( 𝜑 → ( ( 𝜓𝜒 ) → ( 𝜃𝜏 ) ) )
3 1 pm4.71da ( 𝜑 → ( 𝜓 ↔ ( 𝜓𝜒 ) ) )
4 3 2 sylbid ( 𝜑 → ( 𝜓 → ( 𝜃𝜏 ) ) )
5 1 4 imbi12d2 ( 𝜑 → ( ( 𝜓𝜃 ) ↔ ( 𝜒𝜏 ) ) )