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arXiv · 1906.03409

Twin semigroups and delay equations

Odo Diekmann·Sjoerd Verduyn Lunel
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Abstract

In the standard theory of delay equations, the fundamental solution does not 'live' in the state space. To eliminate this age-old anomaly, we enlarge the state space. As a consequence, we lose the strong continuity of the solution operators and this, in turn, has as a consequence that the Riemann integral no longer suffices for giving meaning to the variation-of-constants formula. To compensate, we develop the Stieltjes-Pettis integral in the setting of a norming dual pair of spaces. Part I provides general theory, Part II deals with "retarded" equations, and in Part III we show how the Stieltjes integral enables incorporation of unbounded perturbations corresponding to neutral delay equations.

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Odo Diekmann, Sjoerd Verduyn Lunel. 2019-06-08. Twin semigroups and delay equations. https://arxiv.org/abs/1906.03409

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