reserve o,m for set;
reserve C for Cartesian_category;
reserve a,b,c,d,e,s for Object of C;
reserve C for Cocartesian_category;
reserve a,b,c,d,e,s for Object of C;

theorem
  dom(init a) = EmptyMS C & cod(init a) = a
proof
  EmptyMS C is initial & init a = init(EmptyMS C,a) by Def26,Th56;
  hence thesis by CAT_3:38;
end;
