Description: The property of relation R being hereditary in class A . (Contributed by RP, 27-Mar-2020)
Ref | Expression | ||
---|---|---|---|
Assertion | df-he | |
Step | Hyp | Ref | Expression |
---|---|---|---|
0 | cR | |
|
1 | cA | |
|
2 | 1 0 | whe | |
3 | 0 1 | cima | |
4 | 3 1 | wss | |
5 | 2 4 | wb | |