Description: Substitution of equal classes into the negation of a binary relation. (Contributed by Glauco Siliprandi, 3-Jan-2021)
| Ref | Expression | ||
|---|---|---|---|
| Hypotheses | eqnbrtrd.1 | |- ( ph -> A = B ) | |
| eqnbrtrd.2 | |- ( ph -> -. B R C ) | ||
| Assertion | eqnbrtrd | |- ( ph -> -. A R C ) | 
| Step | Hyp | Ref | Expression | 
|---|---|---|---|
| 1 | eqnbrtrd.1 | |- ( ph -> A = B ) | |
| 2 | eqnbrtrd.2 | |- ( ph -> -. B R C ) | |
| 3 | 1 | breq1d | |- ( ph -> ( A R C <-> B R C ) ) | 
| 4 | 2 3 | mtbird | |- ( ph -> -. A R C ) |