Description: Commutative law for restriction and difference. (Contributed by AV, 7-Jun-2021)
Ref | Expression | ||
---|---|---|---|
Assertion | resdifcom | |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | indif1 | |
|
2 | df-res | |
|
3 | df-res | |
|
4 | 3 | difeq1i | |
5 | 1 2 4 | 3eqtr4ri | |