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JOURNALS // Matematicheskii Sbornik // Archive

Mat. Sb., 2025 Volume 216, Number 12, Pages 3–24 (Mi sm10319)

Unitary transform diagonalizing the confluent hypergeometric kernel

S. M. Gorbunovabc

a Ivannikov Institute for System Programming of the Russian Academy of Science, Moscow, Russia
b Moscow Institute of Physics and Technology, Dolgoprudny, Moscow Region, Russia
c Steklov Mathematical Institute of Russian Academy of Sciences, Moscow, Russia

Abstract: We consider the image of the operator inducing the determinantal point process with confluent hypergeometric kernel. The space is described as the image of $L_2[0, 1]$ under a unitary transformation generalizing the Fourier transform. For the derived transformation we prove a counterpart of the Paley–Wiener theorem. We use this theorem to prove that the corresponding analogue of the Wiener–Hopf operator is a unitary equivalent of the usual Wiener–Hopf operator, which implies that it shares the same factorization properties and Widom's trace formula. Finally, using the transformation introduced we present explicit formulae for the hierarchical decomposition of the image of the operator induced by the confluent hypergeometric kernel.
Bibliography: 23 titles.

Keywords: confluent hypergeometric kernel, Hilbert space with reproducing kernel, Jacobi orthogonal polynomials, Paley–Wiener theorem.

MSC: Primary 60G55; Secondary 33C10, 44À15

Received: 06.04.2025 and 27.09.2025

DOI: 10.4213/sm10319


 English version:
Sbornik: Mathematics, 2025, 216:12, 1643–1663

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© Steklov Math. Inst. of RAS, 2026