reserve C for CatStr;
reserve f,g for Morphism of C;
reserve C for non void non empty CatStr,
  f,g for Morphism of C,
  a,b,c,d for Object of C;
reserve o,m for set;
reserve B,C,D for Category;
reserve a,b,c,d for Object of C;
reserve f,f1,f2,g,g1,g2 for Morphism of C;
reserve f,f1,f2 for Morphism of a,b;
reserve f9 for Morphism of b,a;
reserve g for Morphism of b,c;
reserve h,h1,h2 for Morphism of c,d;

theorem Th63:
  for T being (Functor of C,D),c being Object of C holds T.(id c)
  = id((Obj T).c)
proof
  let T be (Functor of C,D),c be Object of C;
  ex d being Object of D st T.(id c) = id d by Def19;
  hence thesis by Th62;
end;
