Determining Closure of Sets of Attributes Based on Karnaugh Map

Determining closure of any set of attributes is a basic operation in theory of functional dependencies. The relative algorithm often needs verify a given set of functional dependencies many times to get the final result, so it is time-consuming. In this paper we put forward a new algorithm for the problem. From given set of functional dependencies a new set of simplest functional dependencies is obtained through Karnaugh map. The new set includes all functional dependencies implied by original one. And these functional dependencies are not trivial and have no redundant attributes in their left sides. The algorithm can output the closure of any set of attributes by only scanning the new set once. Q-M method can replace Karnaugh map effectively in the case of greater number of attributes.