Metamath Proof Explorer


Theorem 2alanimi

Description: Removes two universal quantifiers from a statement. (Contributed by Andrew Salmon, 24-May-2011)

Ref Expression
Hypothesis 2alanimi.1 φψχ
Assertion 2alanimi xyφxyψxyχ

Proof

Step Hyp Ref Expression
1 2alanimi.1 φψχ
2 1 alanimi yφyψyχ
3 2 alanimi xyφxyψxyχ