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JOURNALS // Matematicheskie Zametki // Archive

Mat. Zametki, 1976 Volume 20, Issue 4, Pages 511–520 (Mi mzm7871)

This article is cited in 3 papers

Some stability properties for analytic operator functions

Yu. L. Shmul'yan

Odessa Institute of Marine Engineers

Abstract: Let $\mathfrak G$ be a connected, finite-dimensional, complex analytic manifold; let T(lambda) be an analytic function defined on $\mathfrak G$, whose values are $J$-biexpanding operators on a $J$-space $H$. Let $\mathfrak R(A)$ denote the range of $A$. The following assertions are proved: 1. The lineals $\mathfrak R(\sqrt{T(\lambda)^*JT(\lambda)-J})\equiv\mathfrak R$ and $\mathfrak R(\sqrt{T(\lambda)JT(\lambda)^*-J})\equiv\mathfrak R_*$ do not depend on $\lambda$. 2. For arbitrary $\lambda,\mu\in\mathfrak G$ we have $\mathfrak R(T(\lambda)-T(\mu))\subset\mathfrak R_*$, $\mathfrak R(T(\lambda)^*-T(\mu)^*)\subset\mathfrak R$.

Received: 19.07.1974


 English version:
Mathematical Notes, 1976, 20:4, 843–848

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