reserve A,B,C for Category,
  F,F1 for Functor of A,B;
reserve o,m for set;
reserve t for natural_transformation of F,F1;

theorem
  Functors([:A,B:],C) ~= Functors(A,Functors(B,C))
proof
  take export(A,B,C);
  thus thesis;
end;
