In order to pass this assignment you have to get at least two of the following four exercises right. (Minor mistakes may be accepted.)

  1. State and give a brief explanation of the Church-Turing thesis.

  2. Give an example of a function on the natural numbers (from  to ) that is:

  3. Is ℕ × Bool countable? Provide a proof. (Bool is a set with two elements, true and false.)

  4. [BN] Is ℕ → Bool countable? Provide a proof.

(Exercises marked with [BN] are based on exercises from a previous version of this course, given by Bengt Nordström.)