Suppose $4$ tasks $($T$1,$ T$2,$ T$3,$ T$4)$ are to be assigned to $,C3,C4,C5,C6,C7),$ and that $T1$ can't be assigned to $C1$ or $C2,T2$ can't be assigned to $C2$ or $C3,$ and $T3$ can't be assigned to $C5,C6,$ or $C7.$ Write down some properties $P_i$ and define some sets $A_i.$