Metamath Proof Explorer


Theorem rnresss

Description: The range of a restriction is a subset of the whole range. (Contributed by Glauco Siliprandi, 17-Aug-2020)

Ref Expression
Assertion rnresss ran A B ran A

Proof

Step Hyp Ref Expression
1 resss A B A
2 1 rnssi ran A B ran A