let L be non empty LattStr ; ( L is meet-idempotent & L is meet-associative & L is meet-commutative & L is satisfying_QLT1 & L is join-idempotent & L is join-associative & L is join-commutative & L is satisfying_QLT2 & L is QLT-selfdistributive implies L is distributive' )
assume
( L is meet-idempotent & L is meet-associative & L is meet-commutative & L is satisfying_QLT1 & L is join-idempotent & L is join-associative & L is join-commutative & L is satisfying_QLT2 & L is QLT-selfdistributive )
; L is distributive'
then
( ( for v0 being Element of L holds v0 "/\" v0 = v0 ) & ( for v2, v1, v0 being Element of L holds (v0 "/\" v1) "/\" v2 = v0 "/\" (v1 "/\" v2) ) & ( for v1, v0 being Element of L holds v0 "/\" v1 = v1 "/\" v0 ) & ( for v0, v2, v1 being Element of L holds (v0 "/\" (v1 "\/" v2)) "\/" (v0 "/\" v1) = v0 "/\" (v1 "\/" v2) ) & ( for v0 being Element of L holds v0 "\/" v0 = v0 ) & ( for v2, v1, v0 being Element of L holds (v0 "\/" v1) "\/" v2 = v0 "\/" (v1 "\/" v2) ) & ( for v1, v0 being Element of L holds v0 "\/" v1 = v1 "\/" v0 ) & ( for v0, v2, v1 being Element of L holds (v0 "\/" (v1 "/\" v2)) "/\" (v0 "\/" v1) = v0 "\/" (v1 "/\" v2) ) & ( for v2, v1, v0 being Element of L holds (((v0 "/\" v1) "\/" v2) "/\" v1) "\/" (v2 "/\" v0) = (((v0 "\/" v1) "/\" v2) "\/" v1) "/\" (v2 "\/" v0) ) )
by LATTICES:def 4, LATTICES:def 5, LATTICES:def 6, LATTICES:def 7, SHEFFER1:def 9, ROBBINS1:def 7;
then
for v1, v2, v3 being Element of L holds v1 "\/" (v2 "/\" v3) = (v1 "\/" v2) "/\" (v1 "\/" v3)
by ThQLT3;
hence
L is distributive'
by SHEFFER1:def 5; verum