空值环境下NFD—NMVD混合强保持逻辑蕴涵问题

The Logic Implication Problem of Strong Holding in Composite NFD-NMVD under Null Value Circumstances

本文讨论了空值环境下的ＮＦＤ－ＮＭＶＤ混合强保持依赖基的定义和求解算法，并讨论了算法的有效性和完备性，给出了ＮＦＤ－ＮＭＶＤ混合推导公理、强保持集属性闭包的求解算法，从而解决了ＮＦＤ－ＮＭＶＤ混合情况下的强保持逻辑蕴涵问题。

In this paper,the definition of strong holding dependency basis in composite NFDNMVD and the algorithm are discussed,the availability and completeness of the algorithm are discussed,and the algorithms to find out composite NFD-NMVD inferring axiom and closure of set of the strong holding attribute are given. And as a result,the logic implication problem of strong holding in composite NFD-NMVD is solved.