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 𝐻C
Assertion pjfi ( proj𝐻 ) : ℋ ⟶ ℋ

Proof

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