Let A be the set of all functions f:Z→Z and R be a relation on A such that R={(f,g):f(0)=g(1) and f(1)=g(0)}. Then R is :
Solutions · 1
Official solution
For R to be reflexive, (f,f) must be in R.
The means f(0)=f(1) and f(1)=f(0) must be true for all f.
But f(0)=f(1) always
Therefore, R is not reflexive
If (f,g)∈R, then f(0)=g(1) and f(1)=g(0)
\[∵f(0)=g(1)⇒g(1)=f(0) and f(1)=g(0)⇒g(0)=f(1)\]
R is symmetric
If (f,g)∈R and (g,h)∈R, then f(0)=g(1), f(1)=g(0),g(0)=n(1)&g(1)=h(0)
Since, f(0)=g(1) and g(1)=h(0), then f(0) is not necessarily equal to h(0).
Therefore, R is not transitive.
∴ The relation R is symmetric but not reflexive or transitive.