theorem eqsubsnabd (G: wff) (a: nat) {x: nat} (p: wff x):
$ G -> p -> x = a $ >
$ G -> subsn {x | p} $;
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | subsnss | {x | p} C_ {x | x = a} -> subsn {x | x = a} -> subsn {x | p} |
|
| 2 | hyp h | G -> p -> x = a |
|
| 3 | 2 | ssabd | G -> {x | p} C_ {x | x = a} |
| 4 | subsnsn2 | subsn {x | x = a} |
|
| 5 | 4 | a1i | G -> subsn {x | x = a} |
| 6 | 1, 3, 5 | sylc | G -> subsn {x | p} |