Metamath Proof Explorer


Theorem oldmj1

Description: De Morgan's law for join in an ortholattice. ( chdmj1 analog.) (Contributed by NM, 6-Nov-2011)

Ref Expression
Hypotheses oldmm1.b B=BaseK
oldmm1.j ˙=joinK
oldmm1.m ˙=meetK
oldmm1.o ˙=ocK
Assertion oldmj1 KOLXBYB˙X˙Y=˙X˙˙Y

Proof

Step Hyp Ref Expression
1 oldmm1.b B=BaseK
2 oldmm1.j ˙=joinK
3 oldmm1.m ˙=meetK
4 oldmm1.o ˙=ocK
5 1 2 3 4 oldmm4 KOLXBYB˙˙X˙˙Y=X˙Y
6 5 fveq2d KOLXBYB˙˙˙X˙˙Y=˙X˙Y
7 olop KOLKOP
8 7 3ad2ant1 KOLXBYBKOP
9 ollat KOLKLat
10 9 3ad2ant1 KOLXBYBKLat
11 1 4 opoccl KOPXB˙XB
12 7 11 sylan KOLXB˙XB
13 12 3adant3 KOLXBYB˙XB
14 1 4 opoccl KOPYB˙YB
15 7 14 sylan KOLYB˙YB
16 15 3adant2 KOLXBYB˙YB
17 1 3 latmcl KLat˙XB˙YB˙X˙˙YB
18 10 13 16 17 syl3anc KOLXBYB˙X˙˙YB
19 1 4 opococ KOP˙X˙˙YB˙˙˙X˙˙Y=˙X˙˙Y
20 8 18 19 syl2anc KOLXBYB˙˙˙X˙˙Y=˙X˙˙Y
21 6 20 eqtr3d KOLXBYB˙X˙Y=˙X˙˙Y