Is r(t)\displaystyle {r}{\left({t}\right)} represented in the list of ordered pairs below a function?

r(t)={(4,6),(3,9),(2,3),(0,8),(0,10),(1,4)}\displaystyle {r}{\left({t}\right)}={\left\lbrace{\left(-{4},{6}\right)},{\left(-{3},-{9}\right)},{\left(-{2},-{3}\right)},{\left({0},-{8}\right)},{\left({0},-{10}\right)},{\left({1},-{4}\right)}\right\rbrace}