For a set of Y real numbers define a function C_{Y}by;

C_{Y}(x)= {1 if x ∈Y,

0 if x is not ∈ Y.

Let Y and Z be a set of real numbers, find expressions for C_{YUZ}and C_{ynz}

YUZ={x∈R|x∈Y or x∈Z}

ynz={x∈R|x∈Y and x∈Z}

so i know what C_{y}is but I'm unsure of what C_{z}is and what I am suppose to do. Help would be greatly appreciated.