Metamath Proof Explorer


Theorem rp-intrabeq

Description: Equality theorem for supremum of sets of ordinals. (Contributed by RP, 23-Jan-2025)

Ref Expression
Assertion rp-intrabeq
|- ( A = B -> |^| { x e. On | A. y e. A y C_ x } = |^| { x e. On | A. y e. B y C_ x } )

Proof

Step Hyp Ref Expression
1 raleq
 |-  ( A = B -> ( A. y e. A y C_ x <-> A. y e. B y C_ x ) )
2 1 rabbidv
 |-  ( A = B -> { x e. On | A. y e. A y C_ x } = { x e. On | A. y e. B y C_ x } )
3 2 inteqd
 |-  ( A = B -> |^| { x e. On | A. y e. A y C_ x } = |^| { x e. On | A. y e. B y C_ x } )