Description: Characterization of the elements of a restricted identity relation. (Contributed by BJ, 28-Aug-2022) (Proof shortened by Peter Mazsa, 9-Sep-2022)
Ref | Expression | ||
---|---|---|---|
Assertion | elrid |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | df-res | ||
2 | 1 | eleq2i | |
3 | elidinxp | ||
4 | inv1 | ||
5 | 4 | rexeqi | |
6 | 2 3 5 | 3bitri |