Determine whether each of the following relations are reflexive, symmetric and transitive:
(iii) Relation R in the set A = {1, 2, 3, 4, 5, 6} as
R = {(x, y): y is divisible by x}
(a) For reflexive, we know that x is divisible by x for all xϵA.
∴(x,x)ϵR for all xϵR. So, R is reflexive.
(b)For symmetry, we know that x is divisible by 2. This means that (2,6)ϵR but (6,2) doesnotbelongtoR. So, R is not symmetric.
(c)For transitiviety, let (x,y)\ belongs R and (y,z)ϵR, then z is divisible by x.
⇒(x,z)ϵR
For example, 2 is divisible by 1,4 is divisible by 2
So, 4 is divisible by 1 so, R is transitive.