Derived conjunction and algorithm to close value block in the database model of block form

Abstract

In the database model of block form, from the results of the research on derived formulas, this article shows how to construct the derived conjunction to receive T_r as the truth block, the main results of this research has demonstrated the necessary and sufficient conditions for a logical formula to be expressed in terms of the derived equations. From these results, this article continues to propose the concepts of T_r value block, closed value block with multiplication & T*, and propose algorithm to make closed value block in database model of block form, the results of this algorithm have found that the smallest truth block T* contains the smallest truth block satisfying: T* contains the element e unit and the z zero element and closes with the & operator. In special cases when the index set consists of 1 element, the volume degenerates into a relationship, this result coincides with the results researched by the authors in the relational database model.