Metamath Proof Explorer


Theorem chdmm1i

Description: De Morgan's law for meet in a Hilbert lattice. (Contributed by NM, 21-Jun-2004) (New usage is discouraged.)

Ref Expression
Hypotheses ch0le.1 A C
chjcl.2 B C
Assertion chdmm1i A B = A B

Proof

Step Hyp Ref Expression
1 ch0le.1 A C
2 chjcl.2 B C
3 1 choccli A C
4 2 choccli B C
5 3 4 chub1i A A B
6 3 4 chjcli A B C
7 1 6 chsscon1i A A B A B A
8 5 7 mpbi A B A
9 4 3 chub2i B A B
10 2 6 chsscon1i B A B A B B
11 9 10 mpbi A B B
12 8 11 ssini A B A B
13 1 2 chincli A B C
14 6 13 chsscon1i A B A B A B A B
15 12 14 mpbi A B A B
16 inss1 A B A
17 13 1 chsscon3i A B A A A B
18 16 17 mpbi A A B
19 inss2 A B B
20 13 2 chsscon3i A B B B A B
21 19 20 mpbi B A B
22 13 choccli A B C
23 3 4 22 chlubii A A B B A B A B A B
24 18 21 23 mp2an A B A B
25 15 24 eqssi A B = A B