1. Let T = {a, b, c, d}.

a. Find an example of a relation of this set that is transitive, but neither reflexive nor symmetric.

For this one I had { (a,b) (b,c) (a,c) }. I am not sure if this is correct.

b. Find an example of a relation on this set that is both transitive and symmetric, but not reflexive.

For this one I came up with { (a, b) (b, c) (a, c) (b, a) (c, b) (c, a) }. Is this correct?