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Seminar "Complex analysis in several variables" (Vitushkin Seminar)
December 5, 2012 16:45, Moscow, Moscow State University, Room 13-06
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Integer-valued characteristics of solutions of a non-commutative sigma-model
A. V. Domrina |
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This page: | 143 |
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Abstract:
We consider solutions of a noncommutative sigma-model (quantum analogues of harmonic two-spheres in a unitary group) that can be represented as finite-dimensional perturbations of the identity operator in a Hilbert space. Such solutions have three integer-valued characteristics: the normalized energy $e$, the canonical rank $r$, and the minimal uniton number $u$. We prove that always $e\geq r\geq u$ and $2e\geq u(u+1)$ (till
now, it was known only that $e\geq r$ and $e\geq u$) and discuss the issue of sufficiency of these inequalities for the existence of a solution with such characteristics.
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