Description: Formula-building deduction for class substitution. (Contributed by NM, 10-Nov-2005) (Revised by Mario Carneiro, 1-Sep-2015)
Ref | Expression | ||
---|---|---|---|
Hypothesis | csbeq2dv.1 | ||
Assertion | csbeq2dv |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | csbeq2dv.1 | ||
2 | 1 | eleq2d | |
3 | 2 | sbcbidv | |
4 | 3 | abbidv | |
5 | df-csb | ||
6 | df-csb | ||
7 | 4 5 6 | 3eqtr4g |