Metamath Proof Explorer


Theorem chcv1

Description: The Hilbert lattice has the covering property. Proposition 1(ii) of Kalmbach p. 140 (and its converse). (Contributed by NM, 11-Jun-2004) (New usage is discouraged.)

Ref Expression
Assertion chcv1 A C B HAtoms ¬ B A A A B

Proof

Step Hyp Ref Expression
1 atom1d B HAtoms x x 0 B = span x
2 spansncv2 A C x ¬ span x A A A span x
3 sseq1 B = span x B A span x A
4 3 notbid B = span x ¬ B A ¬ span x A
5 oveq2 B = span x A B = A span x
6 5 breq2d B = span x A A B A A span x
7 4 6 imbi12d B = span x ¬ B A A A B ¬ span x A A A span x
8 2 7 syl5ibrcom A C x B = span x ¬ B A A A B
9 8 adantld A C x x 0 B = span x ¬ B A A A B
10 9 rexlimdva A C x x 0 B = span x ¬ B A A A B
11 10 imp A C x x 0 B = span x ¬ B A A A B
12 1 11 sylan2b A C B HAtoms ¬ B A A A B
13 atelch B HAtoms B C
14 chjcl A C B C A B C
15 cvpss A C A B C A A B A A B
16 14 15 syldan A C B C A A B A A B
17 chnle A C B C ¬ B A A A B
18 16 17 sylibrd A C B C A A B ¬ B A
19 13 18 sylan2 A C B HAtoms A A B ¬ B A
20 12 19 impbid A C B HAtoms ¬ B A A A B