EDB — 04R

Exercises

1. [04R] Prerequisites:[04P]↺↻,[03H]↺↻,[22F]↺↻.Difficulty:*.(Solved on 2022-10-13
   in parte)

   Let \(A\) infinite. Show that \(|D× A|=|A|\) for every non-empty countable set \(D\) . ¹

   (A possible solution uses [04P]↺↻)

   Solution 1

   [04S]↺↻

   (Another possible solution uses Zermelo’s theorem, [22F]↺↻ and [03H]↺↻; in this case [04P]↺↻ becomes a corollary of this result.)

   Solution 2

   [04T]↺↻