Metamath Proof Explorer


Theorem ssrind

Description: Add right intersection to subclass relation. (Contributed by Glauco Siliprandi, 2-Jan-2022)

Ref Expression
Hypothesis ssrind.1 φAB
Assertion ssrind φACBC

Proof

Step Hyp Ref Expression
1 ssrind.1 φAB
2 ssrin ABACBC
3 1 2 syl φACBC