322 research outputs found

    Surjectivity of differential operators and linear topological invariants for spaces of zero solutions

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    We provide a sufficient condition for a linear differential operator with constant coefficients P(D)P(D) to be surjective on C(X)C^\infty(X) and D(X)\mathscr{D}'(X), respectively, where XRdX\subseteq\mathbb{R}^d is open. Moreover, for certain differential operators this sufficient condition is also necessary and thus a characterization of surjectivity for such differential operators on C(X)C^\infty(X), resp. on D(X)\mathscr{D}'(X), is derived. Additionally, we obtain for certain surjective differential operators P(D)P(D) on C(X)C^\infty(X), resp. D(X)\mathscr{D}'(X), that the spaces of zero solutions CP(X)={uC(X);P(D)u=0}C_P^\infty(X)=\{u\in C^\infty(X);\, P(D)u=0\}, resp. DP(X)={uD(X);P(D)u=0}\mathscr{D}_P'(X)=\{u\in\mathscr{D}'(X);\,P(D)u=0\} possess the linear topological invariant (Ω)(\Omega) introduced by Vogt and Wagner in [27], resp. its generalization (PΩ)(P\Omega) introduced by Bonet and Doma\'nski in [1].Comment: 16 pages. This updated version emphasizes the implications of our results for the spaces of zero solutions to possess certain linear topological invariants. Apart from a revised introduction this version contains an additional section on said invariants and surjectivity of differential operators on vector-valued functions/distributions. In our opinion, this update justifies a change of the titl

    The augmented operator of a surjective partial differential operator with constant coefficients need not be surjective

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    For d3d\geq 3 we give an example of a constant coefficient surjective differential operator P(D):D(X)D(X)P(D):\mathscr{D}'(X)\rightarrow\mathscr{D}'(X) over some open subset XRdX\subset\R^d such that P+(D):D(X×R)D(X×R)P^+(D):\mathscr{D}'(X\times\R)\rightarrow\mathscr{D}'(X\times\R) is not surjective, where P+(x1,...,xd+1):=P(x1,...,xd)P^+(x_1,...,x_{d+1}):=P(x_1,...,x_d). This answers in the negative a problem posed by Bonet and Doma\'nski in \cite[Problem 9.1]{Bonet}

    A remark on the frequent hypercyclicity criterion for weighted composition semigroups and an application to the linear von Foerster-Lasota equation

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    We generalize a result for the translation C0C_0-semigroup on Lp(R+,μ)L^p(\R_+,\mu) about the equivalence of being chaotic and satisfying the Frequent Hypercyclicity criterion due to Mangino and Peris to certain weighted composition C0C_0-semigroups. Such C0C_0-semigroups appear in a natural way when dealing with initial value problems for linear first order partial differential operators. We apply our result to the linear von Foerster-Lasota equation arising in mathematical biology. Weighted composition C0C_0-semigroups on Sobolev spaces are also considered.Comment: 12 page

    Dynamics of weighted composition operators on function spaces defined by local properties

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    We study topological transitivity/hypercyclicity and topological (weak) mixing for weighted composition operators on locally convex spaces of scalar-valued functions which are defined by local properties. As main application of our general approach we characterize these dynamical properties for weighted composition operators on spaces of ultradifferentiable functions, both of Beurling and Roumieu type, and on spaces of zero solutions of elliptic partial differential equations. Special attention is given to eigenspaces of the Laplace operator and the Cauchy-Riemann operator, respectively. Moreover, we show that our abstract approach unifies existing results which characterize hypercyclicity, resp. topological mixing, of (weighted) composition operators on the space of holomorphic functions on a simply connected domain in the complex plane, on the space of smooth functions on an open subset of Rd\mathbb{R}^d, as well as results characterizing topological transitiviy of such operators on the space of real analytic functions on an open subset of Rd\mathbb{R}^d.Comment: 35 pages; some minor changes, accepted for publication in Studia Mathematic

    A Distant View of a Snowy Range: Freshfield and Sella on the Tour of Kangchenjunga, 1899

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