Membership problems for data dependencies in relational expressions (Q1060028)

In relational databases, a query can be formulated in terms of a relational algebra expression using projection, selection, restriction, cross product and union. In this paper, we consider a problem, called the membership problem, of determining whether a given dependency d is valid in a given relational expression E over a given database scheme R, that is, whether every instance of the view scheme defined by E satisfies d (assuming that the underlying constraints in R are always satisfied).