Date: Mar 25, 2013 3:37 PM
Author: Ming Wang
Subject: Equivalence relation: describe the distinct equivalence classes

Describe the distinct equivalence classes of the following relation.
Let P be a set of parts shipped to a company from various
suppliers. S is the relation defined on P as follows: For all x, y in P,
x S y<=>x has the same part number and is shipped from the same supplier as y.