theorem sbned (G: wff) {x: nat} (a: nat) (b: nat x) (c: nat): $ G /\ x = a -> b = c $ > $ G -> N[a / x] b = c $;
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | sbnet | A. x (x = a -> b = c) -> N[a / x] b = c |
|
2 | hyp e | G /\ x = a -> b = c |
|
3 | 2 | ialda | G -> A. x (x = a -> b = c) |
4 | 1, 3 | syl | G -> N[a / x] b = c |