Nicola Guglielmi (Gran Sasso Science Institute)
Title:ÌýRobust stability of linear systems of linear delay differential equations.
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We consider a class of nonlinear eigenvalue problems including those arising from stability analysis of linear systems of delay differential equations.Our aim is to compute the pseudospectral abscissa, i.e. the real part of the rightmost point in the pseudospectrum, and detect - for a stable system - when the pseudospectral abscissa vanishes, whichÌýdetermines a nearby system which is not anymore stable. If this occurs for a small perturbation of the considered stable system, this is a sign of lack of robustness.
In analogy to the linear eigenvalue problem we have that it is sufficient to restrict the analysisÌýto rank-1 perturbations of the matrices of the system.ÌýUsing this main result we present a gradient system approach which only requires the computation ofÌýthe spectral abscissa of a sequence of problems obtained by adding rank one updates to the matrices.ÌýIn order to be applied these methods simply require a procedure to compute the rightmost eigenvalueÌýand the corresponding left and right eigenvectors.ÌýIn addition, if the matrices are large and sparse then the computation of the rightmost eigenvalueÌýcan for many classes of nonlinear eigenvalue problems be performed in an efficient way by iterativeÌýalgorithms which only rely on matrix vector multiplication and on solving systems of linear equations,Ìýwhere the structure of the matrices (sparse plus rank one updates) can be exploited.Ìý
Zoom Meeting :
Meeting ID: 853 2731 0903
Password: 383854
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