Metamath Proof Explorer


Theorem chnle

Description: Equivalent expressions for "not less than" in the Hilbert lattice. (Contributed by NM, 9-Jun-2004) (New usage is discouraged.)

Ref Expression
Assertion chnle A C B C ¬ B A A A B

Proof

Step Hyp Ref Expression
1 sseq2 A = if A C A 0 B A B if A C A 0
2 1 notbid A = if A C A 0 ¬ B A ¬ B if A C A 0
3 id A = if A C A 0 A = if A C A 0
4 oveq1 A = if A C A 0 A B = if A C A 0 B
5 3 4 psseq12d A = if A C A 0 A A B if A C A 0 if A C A 0 B
6 2 5 bibi12d A = if A C A 0 ¬ B A A A B ¬ B if A C A 0 if A C A 0 if A C A 0 B
7 sseq1 B = if B C B 0 B if A C A 0 if B C B 0 if A C A 0
8 7 notbid B = if B C B 0 ¬ B if A C A 0 ¬ if B C B 0 if A C A 0
9 oveq2 B = if B C B 0 if A C A 0 B = if A C A 0 if B C B 0
10 9 psseq2d B = if B C B 0 if A C A 0 if A C A 0 B if A C A 0 if A C A 0 if B C B 0
11 8 10 bibi12d B = if B C B 0 ¬ B if A C A 0 if A C A 0 if A C A 0 B ¬ if B C B 0 if A C A 0 if A C A 0 if A C A 0 if B C B 0
12 h0elch 0 C
13 12 elimel if A C A 0 C
14 12 elimel if B C B 0 C
15 13 14 chnlei ¬ if B C B 0 if A C A 0 if A C A 0 if A C A 0 if B C B 0
16 6 11 15 dedth2h A C B C ¬ B A A A B