Metamath Proof Explorer


Theorem colleq12d

Description: Equality theorem for the collection operation. (Contributed by Rohan Ridenour, 11-Aug-2023)

Ref Expression
Hypotheses colleq12d.1 ⊢ φ → F = G
colleq12d.2 ⊢ φ → A = B
Assertion colleq12d ⊢ φ → F Coll A = G Coll B

Proof

Step Hyp Ref Expression
1 colleq12d.1 ⊢ φ → F = G
2 colleq12d.2 ⊢ φ → A = B
3 1 imaeq1d ⊢ φ → F x = G x
4 3 scotteqd ⊢ φ → Scott F x = Scott G x
5 2 4 iuneq12d ⊢ φ → ⋃ x ∈ A Scott F x = ⋃ x ∈ B Scott G x
6 df-coll ⊢ F Coll A = ⋃ x ∈ A Scott F x
7 df-coll ⊢ G Coll B = ⋃ x ∈ B Scott G x
8 5 6 7 3eqtr4g ⊢ φ → F Coll A = G Coll B