Discrete Mathematics
Hans Georg Schaathun
12th November 2015

Discrete Mathematics

First Session — Tuesday 18 August 2015

Repetition Exercises

You should be able to answer these exercises based on Level 1 syllabus. If you find the problems difficult, you should seek answers in previous textbooks.

Exercise 1.1 Rewrite the following formulæ as plain English or Scandinavian sentences:

  1. S = {1,2,5}
  2. x A
  3. A x
  4. A {1,2,3,}
  5. S = n

Exercise 1.2 Consider two sets A = {a,b,c,d} and B = {b,c,e,f}. What are the elements of the following sets

A B  (1) A B  (2) AB sometimes writtenA B  (3)

Exercise 1.3 What do we mean when we say that A and B are disjoint?

Exercise 1.4

  1. Explain what a function is?
  2. Give an example of a function on the real numbers.
  3. Give an example of a function from {1,2} to {a,b,c}

Exercise 1.5 Let f : A B be a function. And suppose y = f(x), and for simplicity, A and B are disjoint. True or false?

Hans Georg Schaathun / hasc@hials.no