Metamath Proof Explorer


Theorem ee220

Description: e220 without virtual deductions. (Contributed by Alan Sare, 12-Jul-2011) (Proof modification is discouraged.) (New usage is discouraged.)

Ref Expression
Hypotheses ee220.1 φψχ
ee220.2 φψθ
ee220.3 τ
ee220.4 χθτη
Assertion ee220 φψη

Proof

Step Hyp Ref Expression
1 ee220.1 φψχ
2 ee220.2 φψθ
3 ee220.3 τ
4 ee220.4 χθτη
5 3 2a1i φψτ
6 1 2 5 4 ee222 φψη