set L = QLTLattice2 ;
Y1:
for x, y being Element of QLTLattice2 holds x "/\" y = y "/\" x
by BINOP_1:def 2;
S1:
for x, y, z being Element of QLTLattice2 holds x "/\" (y "/\" z) = (x "/\" y) "/\" z
by BINOP_1:def 3;
for x being Element of QLTLattice2 holds x "/\" x = x
by BINOP_1:def 4;
hence
( QLTLattice2 is meet-commutative & QLTLattice2 is meet-associative & QLTLattice2 is meet-idempotent )
by Y1, LATTICES:def 6, LATTICES:def 7, S1, SHEFFER1:def 9; verum