Theorem 2alim

Description: Theorem *11.32 in WhiteheadRussell p. 162. Theorem 19.20 of Margaris p. 90 with 2 quantifiers. (Contributed by Andrew Salmon, 24-May-2011)

	Ref	Expression
Assertion	2alim	|- ( A. x A. y ( ph -> ps ) -> ( A. x A. y ph -> A. x A. y ps ) )

Proof

Step	Hyp	Ref	Expression
1		id	|- ( ( ph -> ps ) -> ( ph -> ps ) )
2	1	2al2imi	|- ( A. x A. y ( ph -> ps ) -> ( A. x A. y ph -> A. x A. y ps ) )