The Tan 2θ Theorem for Indefinite Quadratic Forms
نویسندگان
چکیده
A version of the Davis-Kahan Tan 2Θ theorem [SIAM J. Numer. Anal. 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 56 (2006), 511 – 542].
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