E xercise 3.2.10: Suppose we have relation R(A,B,C,D ,E), with some set of FDs, and we wish to project those FDs onto relation S(A, B, C). Give the FDs that hold in S if the FDs for R are:

a) AB >DE, C >E, D >C, and E >A.

b) A > D : BD > E, AC > E, and DE > B.

c) AB > D , AC > E, BC > D , D > A , and E > B.

d) A ---> B, B---> C, C----> D, D -----> E, and E ---->A..

In each case, it is sufficient to give a minimal basis for the full set of FDs of S.

Please give the method and the answer.