1.Prove that an MVD X →→ Y over a relation R can be expressed as the join dependency ;: {XY, X(R − Y )}.
2.Let R be a relation schema with a set F of FDs. Prove that the decomposition of R into R1 and R2 is lossless-join if and only if F+ contains R1 ∩ R2 → R1 or R1 ∩ R2 → R2.