Metamath Proof Explorer


Theorem pjococi

Description: Proof of orthocomplement theorem using projections. Compare ococ . (Contributed by NM, 5-Nov-1999) (New usage is discouraged.)

Ref Expression
Hypothesis pjococ.1 𝐻C
Assertion pjococi ( ⊥ ‘ ( ⊥ ‘ 𝐻 ) ) = 𝐻

Proof

Step Hyp Ref Expression
1 pjococ.1 𝐻C
2 1 ococi ( ⊥ ‘ ( ⊥ ‘ 𝐻 ) ) = 𝐻