:: deftheorem Def7 defines u.t.i. LATTICE5:def 7 :
for A being non empty set
for L being lower-bounded LATTICE
for f being BiFunction of A,L holds
( f is u.t.i. iff for x, y, z being Element of A holds (f . (x,y)) "\/" (f . (y,z)) >= f . (x,z) );