Metamath Proof Explorer


Theorem mapco2

Description: Post-composition (renaming indices) of a mapping viewed as a point. (Contributed by Stefan O'Rear, 5-Oct-2014) (Revised by Stefan O'Rear, 5-May-2015)

Ref Expression
Hypothesis mapco2.3 ⊢ E ∈ V
Assertion mapco2 ⊢ A ∈ B C ∧ D : E ⟶ C → A ∘ D ∈ B E

Proof

Step Hyp Ref Expression
1 mapco2.3 ⊢ E ∈ V
2 mapco2g ⊢ E ∈ V ∧ A ∈ B C ∧ D : E ⟶ C → A ∘ D ∈ B E
3 1 2 mp3an1 ⊢ A ∈ B C ∧ D : E ⟶ C → A ∘ D ∈ B E