theorem Th24:
for
PS being
ParSp for
a,
b,
c being
Element of
PS st
a,
b '||' a,
c holds
(
a,
c '||' a,
b &
b,
a '||' a,
c &
a,
b '||' c,
a &
a,
c '||' b,
a &
b,
a '||' c,
a &
c,
a '||' a,
b &
c,
a '||' b,
a &
b,
a '||' b,
c &
a,
b '||' b,
c &
b,
a '||' c,
b &
b,
c '||' b,
a &
a,
b '||' c,
b &
c,
b '||' b,
a &
b,
c '||' a,
b &
c,
b '||' a,
b &
c,
a '||' c,
b &
a,
c '||' c,
b &
c,
a '||' b,
c &
a,
c '||' b,
c &
c,
b '||' c,
a &
b,
c '||' c,
a &
c,
b '||' a,
c &
b,
c '||' a,
c )