Class is formal languages & automata.

Consider strings w,x,y, and z such that w=xyz. Each row of the following table describes a relationship between y and w. What are the constraints on x, y, and z in terms of whether they must or must not be the empty string in order for the for the relationship to be true. Use the following entries: E if it MUST be the empty string, N if it must NOT be the empty string, and U if it can be, but does not have to be, the empty string. If there is more that one way to achieve the relationship, list each on a separate row, using as few rows as possible for each relationship. Consider strings w,x,y, and z such that w=xyz. Each row of the following table describes a relationship between y and w. What are the constraints on x, y, and z in terms of whether they must or must not be the empty string in order for the for the relationship to be true. Use the following entries: E if it MUST be the empty string, N if it must NOT be the empty string, and U if it can be, but does not have to be, the empty string. If there is more that one way to achieve the relationship, list each on a separate row, using as few rows as possible for each relationship