let L be non empty join-commutative meet-commutative distributive join-idempotent upper-bounded' lower-bounded' distributive' complemented' LattStr ; :: thesis: Bottom L = Bot' L
A1: L is lower-bounded by Th15;
set Y = Bot' L;
for a being Element of L holds
( (Bot' L) "/\" a = Bot' L & a "/\" (Bot' L) = Bot' L ) by Th6;
hence Bottom L = Bot' L by A1, LATTICES:def 16; :: thesis: verum