Given two sets X and Y, we denote the cardinality of X by |X| and the set of all functions from X to Y by YX. Suppose that |A| <= |C| and |B| <= |D|. Show that |BA| <= |DC|. Hint: Construct a function psi: BA --> DC and show that it is injective. Can you please explain why this hint works too?

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A: Solution:-

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A: The complete solutions is in given below