Aizerman's conjecture

In nonlinear control, Aizerman's conjecture states that a nonlinear system with a sector nonlinearity would be stable if the linear system is stable. This conjecture was proven false by the circle criterion.cite journal
author = Atherton, D.P.
coauthors = Siouris, G.M.
year = 1977
title = Nonlinear Control Engineering
journal = Systems, Man and Cybernetics, IEEE Transactions on
volume = 7
issue = 7
pages = 567-568
url = http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=4309773
accessdate = 2008-06-30]

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