Category "formal-languages"

Determining language from a grammar

I'm trying to solve an exercise on grammars and languages. Here is the exercise: Let the grammar G be: G = {V, T, P, S}, V = {S, A, B}, T = {a, b, c}, P = {S

How can the union of X and Y be equal to the intersection of Y and Z (X u Y = Y n Z)?

On which conditions can the equation X u Y = Y n Z be true? I need to prove this equation step by step, but I do not know where to start.