Find all values of a such that this set is a type II region (i.e. the bounds of x can be represented as functions of y, while the bounds of y are constant valued)
-1<y<0, Y<x<-y (union) 0<y<1, -y+a<x<y+a
The Attempt at a Solution
I arrived at a being any value in the bound (-inf, 0}, since if a is a value greater than 0, then the y bounds (0<y<1) start to exist outside of the region bounded by -y+a and y+a. In other words, a must be negative or 0.