A Class of Positive Definite Kernels with Cubic Symmetrization

Authors

DOI:

https://doi.org/10.31652/3041-1955-2026-03-01-01

Keywords:

integral representation, kernels, positive definite function

Abstract

The class of positive definite kernels K(x,y) generated by an entire function k by means of symmetrization associated with cube roots of unity is investigated. For kernels consistent with the spectral structure of the third-order problem u'''=λu, an explicit integral representation of the function k in terms of a nonnegative spectral measure dρ(λ) with compact support is obtained. The obtained formula determines the constructive parameterization of admissible kernels in the considered class and establishes a direct connection between positive definiteness and spectral data.

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Author Biographies

  • Ivanna Andrusyak, Lviv Polytechnic National University
    Candidate of Science in Physіcs and Mathematics, Associate Professor, Department of Higher Mathematics, Lviv Polytechnic National University, 12 Stepan Bandera Street, Lviv 79000, Ukraine
  • Oksana Brodyak, Lviv Polytechnic National University
    Candidate of Science in Physіcs and Mathematics, Associate Professor, Department of Higher Mathematics, Lviv Polytechnic National University, 12 Stepan Bandera Street, Lviv 79000, Ukraine

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Published

2026-05-27

Issue

Section

ARTICLES

How to Cite

A Class of Positive Definite Kernels with Cubic Symmetrization. (2026). Mathematics, Informatics, Physics: Science and Education, 3(1), 1-10. https://doi.org/10.31652/3041-1955-2026-03-01-01