let n be Nat; :: thesis: for A being Subset of (TOP-REAL n) holds BDD A c= A `
let A be Subset of (TOP-REAL n); :: thesis: BDD A c= A `
reconsider D = BDD A as Subset of ((TOP-REAL n) | (A `)) by Th11;
D c= the carrier of ((TOP-REAL n) | (A `)) ;
hence BDD A c= A ` by PRE_TOPC:8; :: thesis: verum