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Metamath Proof Explorer


Theorem pjhf

Description: The mapping of a projection. (Contributed by NM, 24-Apr-2006) (New usage is discouraged.)

Ref Expression
Assertion pjhf ( 𝐻C → ( proj𝐻 ) : ℋ ⟶ ℋ )

Proof

Step Hyp Ref Expression
1 pjhfo ( 𝐻C → ( proj𝐻 ) : ℋ –onto𝐻 )
2 fof ( ( proj𝐻 ) : ℋ –onto𝐻 → ( proj𝐻 ) : ℋ ⟶ 𝐻 )
3 1 2 syl ( 𝐻C → ( proj𝐻 ) : ℋ ⟶ 𝐻 )
4 chss ( 𝐻C𝐻 ⊆ ℋ )
5 3 4 fssd ( 𝐻C → ( proj𝐻 ) : ℋ ⟶ ℋ )