16 Show how to derive the following equivalences by a sequence of transformations using the equivalence rules in Section 13. 123 (E) = 1 (2 (3 (E)))...

13.16 Show how to derive the following equivalences by a sequence of transformations

using the equivalence rules in Section 13.2.1.

a. 1∧2∧3 (E) = 1 (2 (3 (E)))

b. 1∧2 (E1 3 E2) = 1 (E1 3 (2 (E2))), where 2 involves only

attributes from E2