Formalization of Structural Constraints of Relationships in Model „Entity-Relationship”

The basic conceptions of the model „entity-relationship” as entities, relationships, structural constraints of the relationships (index cardinality, participation degree, and structural constraints of kind (min, max)) are considered and formalized in terms of relations theory. For the binary relations two operators (min and max) are introduced; structural constraints are determined in terms of the operators; the main theorem about compatibility of these operators’ values on the source relation and inversion to it is given here.

The Localization Procedures of the Vector of Weighting Coefficients on the Set of Teaching Experts in the Tasks of Consuming

In terms of binary relations the author analyses the task of an individual consumers’ choice on the teaching excerpts set. It is suggested to analyse the function of consumer’s value as additive reduction. For localization of the vector of weighting coefficients of additive reduction the procedures based on metrics of object distance towards the ideal point are suggested.