Description: The # function on _om preserves the ordering. (Contributed by Eric Schmidt, 7-Jul-2026)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | hashnnlt | |- ( ( A e. _om /\ B e. A ) -> ( # ` B ) < ( # ` A ) ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | nnfi | |- ( A e. _om -> A e. Fin ) |
|
| 2 | nnord | |- ( A e. _om -> Ord A ) |
|
| 3 | ordpss | |- ( Ord A -> ( B e. A -> B C. A ) ) |
|
| 4 | 2 3 | syl | |- ( A e. _om -> ( B e. A -> B C. A ) ) |
| 5 | 4 | imp | |- ( ( A e. _om /\ B e. A ) -> B C. A ) |
| 6 | hashpss | |- ( ( A e. Fin /\ B C. A ) -> ( # ` B ) < ( # ` A ) ) |
|
| 7 | 1 5 6 | syl2an2r | |- ( ( A e. _om /\ B e. A ) -> ( # ` B ) < ( # ` A ) ) |