Metamath Proof Explorer


Theorem rspcsbela

Description: Special case related to rspsbc . (Contributed by NM, 10-Dec-2005) (Proof shortened by Eric Schmidt, 17-Jan-2007)

Ref Expression
Assertion rspcsbela A B x B C D A / x C D

Proof

Step Hyp Ref Expression
1 rspsbc A B x B C D [˙A / x]˙ C D
2 sbcel1g A B [˙A / x]˙ C D A / x C D
3 1 2 sylibd A B x B C D A / x C D
4 3 imp A B x B C D A / x C D