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 Th56:
  init a = init(EmptyMS C,a)
proof
  EmptyMS C is initial by Def26;
  hence thesis by CAT_3:40;
end;
