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bibkey: derkachkovalyov2017indefinitestieltjes authors: Vladimir Derkach and Ivan Kovalyov year: 2017 title: An operator approach to the indefinite Stieltjes moment problem doi: 10.1007/s10958-017-3573-3 claim: Generalized Stieltjes classes separate the negative-square index of a Nevanlinna function from the index of its coordinate-localized transform zf. strata_touched:

  • D5/S3/Weil/Pick/LocalizedStieltjesNevanlinnaKernel license: citation-only triage: anchor

An operator approach to the indefinite Stieltjes moment problem

Derkach and Kovalyov define the generalized Nevanlinna class by the number of negative squares of the Nevanlinna kernel. Their generalized Stieltjes class records two indices: one for a function f and one for the coordinate-localized function z f(z). This is the mature operator-theoretic source for separating mass positivity from support-localized positivity in the finite atomic model.

The present formalization uses only the one-atom algebraic identity. It does not formalize the paper’s Pontryagin-space operator model, Schur algorithm, moment problem, Padé approximation, or realization theory.

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  • 2026-09-02: Queried generalized Stieltjes functions negative squares z f generalized Nevanlinna class and found the 2017 journal article together with the exact definition f in N_kappa and z f in N_k.
  • 2026-09-02: Queried the title and DOI. The journal record verified the authors, pages 33-67, volume 227, and DOI 10.1007/s10958-017-3573-3.
  • 2026-09-02: Queried related primary preprints and found the authors’ Schur algorithm paper arXiv:1606.03371 and full indefinite moment treatment arXiv:2002.07456.

Verified locator

  • DOI: https://doi.org/10.1007/s10958-017-3573-3
  • Journal metadata and abstract: https://journals.rcsi.science/1072-3374/article/view/240089
  • Related Schur-algorithm preprint: https://arxiv.org/abs/1606.03371
  • Related full-problem preprint: https://arxiv.org/abs/2002.07456