A relation in a set $\mathit{A}$ is called reflexive relation, if each element of $\mathit{A}$ is related to itself.
as for set $\mathrm{A}=\left\{1,2\right\}$ reflexive relation will be $\mathrm{R}=\left\{\left(1,1\right),\left(2,2\right)\right\}$