About construction of analytical definition of k-value threshold function

Task: In [2] proposed a few methods for finding coefficients of linear form of Boolean threshold function. These methods are founding on using coefficients of characteristic vector, as first approximation of coefficients of linear form, and then a few algorithms for correction of this approximation. In this paper submitted for consideration the question of finding coefficients of linear form of k-value threshold function.
Model: In this paper submitted a few interpretations of closeness of two k-value functions by definition of multiplication, differential and quadratic coefficients, also expansion coefficients and increase coefficients. Considered potential of these coefficients to approximate the coefficients of linear form and possibility of further correction.
Findings: In this paper made the conclusion that expansion coefficients and increase coefficients are better for approximation the coefficients of linear form. Submitted algorithm for finding coefficients of linear form of k-value threshold function funding on increase coefficients.