Theorem 2sp

Description: A double specialization (see sp ). Another double specialization, closer to PM*11.1, is 2stdpc4 . (Contributed by BJ, 15-Sep-2018)

	Ref	Expression
Assertion	2sp	$$⊢\forall x\forall y\phi \to \phi$$

Proof

Step	Hyp	Ref	Expression
1		sp	$$⊢\forall y\phi \to \phi$$
2	1	sps	$$⊢\forall x\forall y\phi \to \phi$$