1) A relation is a set of ordered pairs selected from the cross product
of sets A and B, A x B. A relation may satisfy one of the following
properties; reflexive, symmetric, anti-symmetric and transitive
properties. Identify the properties which the following relations
hold: x is the parent of y,where x and y are elements of sets A and B, respectively.
2) How does the principle of inclusion and exclusion relate to the
rule for determining the cardinal number of the union of two or
more sets discussed in chapter 3.3?