Let A = {1, 2, 3}, and let R1 = {(1, 1), (1, 3), (3, 1), (2, 2), (2, 1), (3, 3)}, R2 = {(2, 2), (3, 1), (1, 3)}, R3 = {(1, 3), (3, 3)}. Find whether or not each of the relations R1, R2, R3 on A is (i) reflexive (ii) symmetric (iii) transitive.
(1) R1
Reflexivity:
Here,
$(1,1),(2,2),(3,3) \in R$
So, $R_{1}$ is reflexive.
Symmetry:
Here,
$(2,1) \in R_{1}$, but $(1,2) \notin R_{1}$
So, $R_{1}$ is not symmetric.
Transitivity:
Here, $(2,1) \in R_{1}$ and $(1,3) \in R_{1}$, but $(2,3) \notin R_{1}$
So, $R_{1}$ is not transitive.
(2) R2
Reflexivity:
Clearly, $(1,1)$ and $(3,3) \notin R_{2}$
So, $R_{2}$ is not reflexive.
Symmetry:
Here, $(1,3) \in R_{2}$ and $(3,1) \in R_{2}$
So, $R_{2}$ is symmetric.
Transitivity:
Here, $(1,3) \in R_{2}$ and $(3,1) \in R_{2}$
But $(3,3) \notin R_{2}$
So, $R_{2}$ is not transitive.
(3) R3
Reflexivity:
Clearly, $(1,1) \notin R_{3}$
So, $R_{3}$ is not reflexive.
Symmetry:
Here, $(1,3) \in R_{3}$, but $(3,1) \notin R_{3}$
So, $R_{3}$ is not symmetric.
Transitivity:
Here, $(1,3) \in R_{3}$ and $(3,3) \in R_{3}$
Also, $(1,3) \in R_{3}$
So, $R_{3}$ is transitive.
Here,