Metamath Proof Explorer


Theorem cmcm2i

Description: Commutation with orthocomplement. Theorem 2.3(i) of Beran p. 39. (Contributed by NM, 4-Nov-2000) (New usage is discouraged.)

Ref Expression
Hypotheses pjoml2.1 A C
pjoml2.2 B C
Assertion cmcm2i A 𝐶 B A 𝐶 B

Proof

Step Hyp Ref Expression
1 pjoml2.1 A C
2 pjoml2.2 B C
3 1 2 chincli A B C
4 2 choccli B C
5 1 4 chincli A B C
6 3 5 chjcomi A B A B = A B A B
7 2 pjococi B = B
8 7 ineq2i A B = A B
9 8 oveq2i A B A B = A B A B
10 6 9 eqtr4i A B A B = A B A B
11 10 eqeq2i A = A B A B A = A B A B
12 1 2 cmbri A 𝐶 B A = A B A B
13 1 4 cmbri A 𝐶 B A = A B A B
14 11 12 13 3bitr4i A 𝐶 B A 𝐶 B