theorem writeeq3d (_G: wff) (F: set) (a _b1 _b2: nat): $ _G -> _b1 = _b2 $ > $ _G -> write F a _b1 == write F a _b2 $;
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | eqsidd | _G -> F == F |
|
2 | eqidd | _G -> a = a |
|
3 | hyp _h | _G -> _b1 = _b2 |
|
4 | 1, 2, 3 | writeeqd | _G -> write F a _b1 == write F a _b2 |