TY - JOUR

T1 - Exotic indecomposable systems of four subspaces in a Hilbert space

AU - Enomoto, Masatoshi

AU - Watatani, Yasuo

N1 - Copyright:
Copyright 2007 Elsevier B.V., All rights reserved.

PY - 2007/10

Y1 - 2007/10

N2 - We study the relative position of four (closed) subspaces in a Hilbert space. For any positive integer n, we give an example of exotic indecomposable system S of four subspaces in a Hilbert space whose defect is 2n+1/3. By an exotic system, we mean a system which is not isomorphic to any closed operator system under any permutation of subspaces. We construct the examples using certain nice sequences construced by Jiang and Wang in their study of strongly irreducible operators.

AB - We study the relative position of four (closed) subspaces in a Hilbert space. For any positive integer n, we give an example of exotic indecomposable system S of four subspaces in a Hilbert space whose defect is 2n+1/3. By an exotic system, we mean a system which is not isomorphic to any closed operator system under any permutation of subspaces. We construct the examples using certain nice sequences construced by Jiang and Wang in their study of strongly irreducible operators.

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U2 - 10.1007/s00020-007-1512-2

DO - 10.1007/s00020-007-1512-2

M3 - Article

AN - SCOPUS:35148853250

VL - 59

SP - 149

EP - 164

JO - Integral Equations and Operator Theory

JF - Integral Equations and Operator Theory

SN - 0378-620X

IS - 2

ER -