Metamath Proof Explorer


Theorem chpsscon3

Description: Hilbert lattice contraposition law for strict ordering. (Contributed by NM, 12-Jun-2004) (New usage is discouraged.)

Ref Expression
Assertion chpsscon3 ACBCABBA

Proof

Step Hyp Ref Expression
1 chsscon3 ACBCABBA
2 chsscon3 BCACBAAB
3 2 ancoms ACBCBAAB
4 3 notbid ACBC¬BA¬AB
5 1 4 anbi12d ACBCAB¬BABA¬AB
6 dfpss3 ABAB¬BA
7 dfpss3 BABA¬AB
8 5 6 7 3bitr4g ACBCABBA