If A ={1,2,3,4}, define relations on A which have properties of being
(i) Reflexive, transitive but not symmetric.
(ii) symmetric but neither reflexive nor transitive.
(iii) reflexive,symmetric and transitive.
(i) Given that, A={1,2,3,4}
Let {R1={(1,1),(1,2),(2,3),(2,2),(1,3),(3,3)}
R1 is reflexive, since, (1,1)(2,2)(3,3) lie in R1.
Now. (1,2)∈R1,(2,3)∈R1⇒(1,3)∈R1
Hence, R1 is also transitive but (1,2)∈R1 whereas (2,1)/∈R1.
So, it is not symmetric.
(ii) Given that, A={1,2,3,4}
Let R2={(1,2),(2,1)}
Now, (1,2)∈R2.(2,1)∈R2
So, it is symmetric. Since (,1) is not an element, it is neither reflexive of transitive.
(iii) Given that, A={1,2,3,4}
Let R3={(1,2),(2,1),(1,1),(2,2),(3,3),(1,3)(3,1),(2,3)}
Hence, R3 is reflexive, symmetric and transitive.