Given a function module which implements function Z= F(X, Y), which defined as follows:
Z = F(X,Y), where X and Y are integer parameters for F. The detailed definition is given below.
| X + Y when 10<=X<=20, and 12<=Y<=30
Z = | X - Y when 0<=X<10, and 0<=Y<12
| 0 under other conditions
Please answer the following questions:
Identify the equivalence classes in [X, Y]. (hints: Considering Z as a function F with X and Y input