Metamath Proof Explorer


Theorem cossssid

Description: Equivalent expressions for the class of cosets by R to be a subset of the identity class. (Contributed by Peter Mazsa, 27-Jul-2021)

Ref Expression
Assertion cossssid R I R I dom R × ran R

Proof

Step Hyp Ref Expression
1 iss2 R I R = I dom R × ran R
2 refrelcoss2 I dom R × ran R R Rel R
3 2 simpli I dom R × ran R R
4 eqss R = I dom R × ran R R I dom R × ran R I dom R × ran R R
5 3 4 mpbiran2 R = I dom R × ran R R I dom R × ran R
6 1 5 bitri R I R I dom R × ran R