We study the problem of the reduction of self-adjoint block matrices B = (B ij ) with given graph by a group of unitary block diagonal matrices. Under the condition that the matrices B 2 and B 4 are orthoscalar, we describe the graphs of block matrices for which this problem is a problem of *-finite, *-tame, or *-wild representation type.
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Translated from Ukrains’kyi Matematychnyi Zhurnal, Vol. 61, No. 10, pp. 1338–1347, October, 2009.
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Omel’chenko, P.V. On reduction of block matrices in a Hilbert space. Ukr Math J 61, 1578–1588 (2009). https://doi.org/10.1007/s11253-010-0299-5
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DOI: https://doi.org/10.1007/s11253-010-0299-5