reserve i, j, k, n for Nat,
  P for Subset of TOP-REAL 2,
  C for connected compact non vertical non horizontal Subset of TOP-REAL 2;

theorem Th12:
  C c= BDD L~Cage(C,n)
proof
  C c= RightComp Cage(C,n) & RightComp Cage(C,n) c= BDD L~Cage(C,n) by Th11,
GOBRD14:35,JORDAN2C:22;
  hence thesis;
end;
