LetΛnkdenote the class of(0,1)square matrices containing in each row and in each column exactlyk1’s. The minimal value ofk, for which the behavior of the permanent inΛnkis not quite studied, isk=3. We give a simple algorithm for calculation of upper magnitudes of permanent inΛn3and consider some extremal problems in a generalized classΛn(α,β,γ), the matrices of which contain in each row and in each column nonzero elementsα,β, andγandn-3zeros.
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