Displaying similar documents to “Stabilization of the wave equation by on-off and positive-negative feedbacks”

Towards parametrizing word equations

H. Abdulrab, P. Goralčík, G. S. Makanin (2010)

RAIRO - Theoretical Informatics and Applications

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Classically, in order to resolve an equation ≈ over a free monoid *, we reduce it by a suitable family ℱ of substitutions to a family of equations ≈ , f ∈ ℱ , each involving less variables than ≈ , and then combine solutions of ≈ into solutions of ≈ . The problem is to get ℱ in a handy form. The method we propose consists in parametrizing the path traces in the so called associated to ≈ . We carry out such a parametrization in the case the prime equations in the graph involve at...

Non-Trapping sets and Huygens Principle

Dario Benedetto, Emanuele Caglioti, Roberto Libero (2010)

ESAIM: Mathematical Modelling and Numerical Analysis

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We consider the evolution of a set Λ ⊂ ℝ 2 according to the Huygens principle: the domain at time , Λ, is the set of the points whose distance from is lower than . We give some general results for this evolution, with particular care given to the behavior of the perimeter of the evoluted set as a function of time. We define a class of sets (non-trapping sets) for which the perimeter is a continuous function of , and we give an algorithm to approximate the evolution. Finally we restrict...