Below is the distribution function:

$\displaystyle F(x)=\frac{1}{4}1_{[0,\infty)}(x)+\frac{1}{2}1_{[1,\infty)}(x)+\frac{1}{4}1_{[2,\infty)(x)$

What does $\displaystyle 1_{[1,\infty)}(x)...$etc mean? Are they like some sort of indicator function? For example in this case, when x= 1/2, it's 0 and when x=3/2, it's 1.