:: deftheorem Def7 defines Closed_Domains_Meet TDLAT_1:def 7 :
for T being TopSpace
for b₂ being BinOp of (Closed_Domains_of T) holds
( b₂ = Closed_Domains_Meet T iff for A, B being Element of Closed_Domains_of T holds b₂ . (A,B) = Cl (Int (A /\ B)) );