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The TAN $2\Theta$ Theorem for Indefinite Quadratic Forms

Spectral Theory 2013-01-30 v1 Mathematical Physics Functional Analysis math.MP

Abstract

A version of the Davis-Kahan Tan 2Θ2\Theta theorem [SIAM J. Numer. Anal. \textbf{7} (1970), 1 -- 46] for not necessarily semibounded linear operators defined by quadratic forms is proven. This theorem generalizes a recent result by Motovilov and Selin [Integr. Equat. Oper. Theory \textbf{56} (2006), 511 -- 542].

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Cite

@article{arxiv.1006.3190,
  title  = {The TAN $2\Theta$ Theorem for Indefinite Quadratic Forms},
  author = {Luka Grubišić and Vadim Kostrykin and Konstantin A. Makarov and Krešimir Veselić},
  journal= {arXiv preprint arXiv:1006.3190},
  year   = {2013}
}
R2 v1 2026-06-21T15:37:05.344Z