Metamath Proof Explorer


Theorem e20an

Description: Conjunction form of e20 . (Contributed by Alan Sare, 15-Jun-2011) (Proof modification is discouraged.) (New usage is discouraged.)

Ref Expression
Hypotheses e20an.1 φ,ψχ
e20an.2 θ
e20an.3 χθτ
Assertion e20an φ,ψτ

Proof

Step Hyp Ref Expression
1 e20an.1 φ,ψχ
2 e20an.2 θ
3 e20an.3 χθτ
4 3 ex χθτ
5 1 2 4 e20 φ,ψτ