Description: Alternate proof of bijust0 ; shorter but using additional intermediate results. (Contributed by NM, 11-May-1999) (Proof shortened by Josh Purinton, 29-Dec-2000) (Revised by BJ, 19-Mar-2020) (Proof modification is discouraged.) (New usage is discouraged.)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | bj-bijust0ALT | |- -. ( ( ph -> ph ) -> -. ( ph -> ph ) ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | id | |- ( ph -> ph ) |
|
| 2 | 1 | bj-nimni | |- -. ( ( ph -> ph ) -> -. ( ph -> ph ) ) |