theorem funceq2d (_G: wff) (F _A1 _A2 B: set): $ _G -> _A1 == _A2 $ > $ _G -> (func F _A1 B <-> func F _A2 B) $;
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | eqsidd | _G -> F == F |
|
| 2 | hyp _h | _G -> _A1 == _A2 |
|
| 3 | eqsidd | _G -> B == B |
|
| 4 | 1, 2, 3 | funceqd | _G -> (func F _A1 B <-> func F _A2 B) |