Question

Which relation is reflexive on \(A=\{1,2\}\)?

Options

• \(R=\phi\)

• \(R=\{(1,1),(2,2),(1,2)\}\)

• \(R=\{(1,2),(2,1)\}\)

• \(R=\{(1,1)\}\)

Answer 1

To check reflexivity, every self-pair must be present. The relation contains both \((1,1)\) and \((2,2)\), so it is reflexive on \(A=\{1,2\}\).