Metamath Proof Explorer


Theorem ee23an

Description: e23an without virtual deductions. (Contributed by Alan Sare, 14-Jul-2011) (Proof modification is discouraged.) (New usage is discouraged.)

Ref Expression
Hypotheses ee23an.1 ( 𝜑 → ( 𝜓𝜒 ) )
ee23an.2 ( 𝜑 → ( 𝜓 → ( 𝜃𝜏 ) ) )
ee23an.3 ( ( 𝜒𝜏 ) → 𝜂 )
Assertion ee23an ( 𝜑 → ( 𝜓 → ( 𝜃𝜂 ) ) )

Proof

Step Hyp Ref Expression
1 ee23an.1 ( 𝜑 → ( 𝜓𝜒 ) )
2 ee23an.2 ( 𝜑 → ( 𝜓 → ( 𝜃𝜏 ) ) )
3 ee23an.3 ( ( 𝜒𝜏 ) → 𝜂 )
4 1 a1dd ( 𝜑 → ( 𝜓 → ( 𝜃𝜒 ) ) )
5 4 2 3 ee33an ( 𝜑 → ( 𝜓 → ( 𝜃𝜂 ) ) )