Metamath Proof Explorer


Theorem cmcm3i

Description: Commutation with orthocomplement. Remark in Kalmbach p. 23. (Contributed by NM, 4-Nov-2000) (New usage is discouraged.)

Ref Expression
Hypotheses pjoml2.1 𝐴C
pjoml2.2 𝐵C
Assertion cmcm3i ( 𝐴 𝐶 𝐵 ↔ ( ⊥ ‘ 𝐴 ) 𝐶 𝐵 )

Proof

Step Hyp Ref Expression
1 pjoml2.1 𝐴C
2 pjoml2.2 𝐵C
3 2 1 cmcm2i ( 𝐵 𝐶 𝐴𝐵 𝐶 ( ⊥ ‘ 𝐴 ) )
4 1 2 cmcmi ( 𝐴 𝐶 𝐵𝐵 𝐶 𝐴 )
5 1 choccli ( ⊥ ‘ 𝐴 ) ∈ C
6 5 2 cmcmi ( ( ⊥ ‘ 𝐴 ) 𝐶 𝐵𝐵 𝐶 ( ⊥ ‘ 𝐴 ) )
7 3 4 6 3bitr4i ( 𝐴 𝐶 𝐵 ↔ ( ⊥ ‘ 𝐴 ) 𝐶 𝐵 )