Reading material

Pages 22-27.

Additional material

unless: or or xor?
Let us consider a simple example. `I will teach a class on Friday' unless `I am sick.' Next, we construct the truth table for this proposition.
I will teach a class on Friday I am sick I will teach a class on Friday unless I am sick
T
T
F
T
F
T
F
T
T
F
F
F
Hence, unless corresponds to xor.

Question

Exercise 3.4