Approximation of the plane point finite system is not only a theoretical problem. It exists also in engineering and economy. The points on the plane are the result of investigation and experience. So, it is highly probable to obtain results – points that are “not congruent” with the...

In standard goal programming (GP) it is assumed that the decision maker (DM) is able to accurately determine goal values. This is unrealistic. Imprecise DM aspiration can be expressed through fuzzy sets whose membership functions represent the DM´s degree of satisfaction. When membership...