There is a question in my book that asks the following:
Suppose we have relation R ( A ,B ,C ,D ,E ) , with some set of FD’s, and we wish to project those FD’s onto relation S(A, B, C). Give the FD’s that hold in S if the FD’s for R are:
A->D BD->E AC->E DE->B
In each case, it is sufficient to give a minimal basis for the full set of FD’s of S.
So I attempted to compute the closure of attributes for all of the subsets of (A,B,C). I could not find any minimal basis of FD's for S. I computer the closure of A, B, C, and AC, but I could not get all of the attributes. A only implies AD, B only implies B, C only implies C and AC only implies ACE. I could not find a functional dependency where there is a attribute on the left hand side that implies all of the attributes on the right hand side.