Description: All variables are effectively bound in a distinct variable specifier. Lemma L19 in Megill p. 446 (p. 14 of the preprint). Usage of this theorem is discouraged because it depends on ax-13 . Use the weaker hbnaev when possible. (Contributed by NM, 13-May-1993) (New usage is discouraged.)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | hbnae | |- ( -. A. x x = y -> A. z -. A. x x = y ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | hbae | |- ( A. x x = y -> A. z A. x x = y ) |
|
| 2 | 1 | hbn | |- ( -. A. x x = y -> A. z -. A. x x = y ) |