Search

Current filters:

Search

Item hits:
  • Article


  • Authors: Lê, Đức Minh (1996)

  • The main purpose of the paper is to study some problems related to the membership problem in the class of functional dependencies. In the paper a way of proving the equivalence of consequences by Armstrong axiomas and by logical values on the basic of the algorithm for finding the closure of a set of attributes. Such as, for a set F of functional dependencies and a functional dependencies and a functional dependency f then the three followings are equivalent: 1) F implies f by Armstrong axiomas, 2) F implies f by logical values, and 3) F implies f by relations. The paper give a necessary and sufficient condition for testing that whether a relation R satiesfies the set F of functional dependencies or not. The paper also mentions some idea for implementing the algorithm to test deduct...

  • Article


  • Authors: Hà, Quang Thụy (1996)

  • Decision Tables has been carried out by S. Pollack, H. Hicks and W.Harrison, Pawlak gave some notations of the rough set into the decision tables in order to study the learning problem. The concept of the attribute dependence also has been carried on by W. Pawlak. In this article, we show two algorithms to determine the attribute dependence, also for the complete dependence and the other for the rough (parthly) dependence. We are study some characters of the dependence for Armstrong's axioms: the transmissive axioms is lost by the rough dependence.