4. Relations and Their Properties (12 points) (1) (2 points) List all of the ordered pairs in the relation R (a, b)lab is (2) (4 points) Determine whether the relation R on the set of all people is even on the set 1,2,3, 4,5) reflexive, symmetric, antisymmetric, and/or transitive, where (a, b) E R if and only if a) There is a book that both a and b have read. (b) a has a higher gpa than b (3) (4 points) Determine whether the relation R on the set of all real numbers is reflexive, symmetric, antisymmetric, and/or transitive, where (x, y) E R if and only if (a) x-y=0 (4) (2 points) Which, if any, of the relations from problems 4.1, 4.2, and 4.3 are equivalence relations