theorem Lemma1: :: ROBBINS5:1

for L being non empty LattStr st L is join-absorbing & ( for v0, v2, v1 being Element of L holds v0 "/\" (v1 "\/" v2) = (v2 "/\" v0) "\/" (v1 "/\" v0) ) holds
for v0 being Element of L holds v0 "/\" v0 = v0