:: deftheorem Def3 defines Domains_Meet TDLAT_1:def 3 :
for T being TopSpace
for b₂ being BinOp of (Domains_of T) holds
( b₂ = Domains_Meet T iff for A, B being Element of Domains_of T holds b₂ . (A,B) = (Cl (Int (A /\ B))) /\ (A /\ B) );