Metamath Proof Explorer


Theorem hashnnlt

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 ) )

Proof

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 ) )