Metamath Proof Explorer


Theorem cmdmdi

Description: Commuting subspaces form a dual modular pair. (Contributed by NM, 25-Apr-2006) (New usage is discouraged.)

Ref Expression
Hypotheses sumdmdi.1 A C
sumdmdi.2 B C
Assertion cmdmdi A 𝐶 B A 𝑀 * B

Proof

Step Hyp Ref Expression
1 sumdmdi.1 A C
2 sumdmdi.2 B C
3 1 choccli A C
4 2 choccli B C
5 3 4 cmmdi A 𝐶 B A 𝑀 B
6 1 2 cmcm4i A 𝐶 B A 𝐶 B
7 dmdmd A C B C A 𝑀 * B A 𝑀 B
8 1 2 7 mp2an A 𝑀 * B A 𝑀 B
9 5 6 8 3imtr4i A 𝐶 B A 𝑀 * B