MMW QUIZ FINALS

from a set A to a set B is a set of ordered pairs (a, b) where a is an element of A and b is an element of B. 

a relation is simply a subset of a ?

Properties of Relation

If R = Ø, means the relation has no element in it.

empty relation is also known as?

if element is related to every other element of A.  Example: R = A x A 

universal relation is also known as?

if every element of set A is related to itself only.  Thus, I = {(a, a), a∈ A} 

If R is a relation from set A to set B, then by interchanging the first and second coordinates of ordered pairs of R, then a new relation is formed B into and this relation is said to be inverse relation denoted by R^-1.

if (x, x) Є R for every x Є X. or reflexive if xRx ∀ x∈X. note: ∀ read as “for all”. It is the one in which every element maps to itself. "Every element is related to itself". A relation R on set A is said to be reflexive if ∀ x∈A, (x, x) Є R