Description: Substitution doesn't affect a constant B (in which x is not free). (Contributed by Mario Carneiro, 14-Oct-2016)
Ref | Expression | ||
---|---|---|---|
Assertion | csbtt | |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | df-csb | |
|
2 | nfcr | |
|
3 | sbctt | |
|
4 | 2 3 | sylan2 | |
5 | 4 | eqabcdv | |
6 | 1 5 | eqtrid | |