Question: a) What is the equivalence class of (1, 2) with respect to the equivalence relation in Exercise?
b) Give an interpretation of the equivalence classes for the equivalence relation R in Exercise.
Exercise: Let R be the relation on the set of ordered pairs of positive integers such that ((a, b), (c, d)) ∈ R if and only if a + d = b + c. Show that R is an equivalence relation.