Metamath Proof Explorer


Theorem ssbri

Description: Inference from a subclass relationship of binary relations. (Contributed by NM, 28-Mar-2007) (Revised by Mario Carneiro, 8-Feb-2015)

Ref Expression
Hypothesis ssbri.1 AB
Assertion ssbri CADCBD

Proof

Step Hyp Ref Expression
1 ssbri.1 AB
2 ssbr ABCADCBD
3 1 2 ax-mp CADCBD