Metamath Proof Explorer


Theorem pjfi

Description: The mapping of a projection. (Contributed by NM, 11-Nov-2000) (New usage is discouraged.)

Ref Expression
Hypothesis pjfn.1 ⊢ 𝐻 ∈ Cℋ
Assertion pjfi ( projℎ ‘ 𝐻 ) : ℋ ⟶ ℋ

Proof

Step Hyp Ref Expression
1 pjfn.1 ⊢ 𝐻 ∈ Cℋ
2 1 pjfni ⊢ ( projℎ ‘ 𝐻 ) Fn ℋ
3 1 pjrni ⊢ ran ( projℎ ‘ 𝐻 ) = 𝐻
4 1 chssii ⊢ 𝐻 ⊆ ℋ
5 3 4 eqsstri ⊢ ran ( projℎ ‘ 𝐻 ) ⊆ ℋ
6 df-f ⊢ ( ( projℎ ‘ 𝐻 ) : ℋ ⟶ ℋ ↔ ( ( projℎ ‘ 𝐻 ) Fn ℋ ∧ ran ( projℎ ‘ 𝐻 ) ⊆ ℋ ) )
7 2 5 6 mpbir2an ⊢ ( projℎ ‘ 𝐻 ) : ℋ ⟶ ℋ