A characterization is presented of the class of stationary processes that have polynomial covariance functions of degree less than or equal to 4 on an interval. The results extend to isotropic random ...

William E. Smith, Ian H. Sloan, Alex H. Opie, Product Integration Over Infinite Intervals I. Rules Based on the Zeros of Hermite Polynomials, Mathematics of ...

Within this framework, polynomial threshold functions (PTFs) represent a class of Boolean functions expressed as the sign of a polynomial, bridging the gap between algebraic methods and ...

Polynomial Threshold Function (PTF): A Boolean function represented as the sign of a real polynomial, used to model decision boundaries in high-dimensional spaces.