Metamath Proof Explorer


Theorem elscottrankeq

Description: Elements in a Scott's trick set have the same rank. (Contributed by BTernaryTau, 9-Jul-2026)

Ref Expression
Assertion elscottrankeq
|- ( ( A e. Scott C /\ B e. Scott C ) -> ( rank ` A ) = ( rank ` B ) )

Proof

Step Hyp Ref Expression
1 simpl
 |-  ( ( A e. Scott C /\ B e. Scott C ) -> A e. Scott C )
2 simpr
 |-  ( ( A e. Scott C /\ B e. Scott C ) -> B e. Scott C )
3 1 2 scottelrankd
 |-  ( ( A e. Scott C /\ B e. Scott C ) -> ( rank ` A ) C_ ( rank ` B ) )
4 2 1 scottelrankd
 |-  ( ( A e. Scott C /\ B e. Scott C ) -> ( rank ` B ) C_ ( rank ` A ) )
5 3 4 eqssd
 |-  ( ( A e. Scott C /\ B e. Scott C ) -> ( rank ` A ) = ( rank ` B ) )