2,101 research outputs found

    Baker's conjecture for functions with real zeros

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    Baker's conjecture states that a transcendental entire functions of order less than 1/2 has no unbounded Fatou components. It is known that, for such functions, there are no unbounded periodic Fatou components and so it remains to show that they can also have no unbounded wandering domains. Here we introduce completely new techniques to show that the conjecture holds in the case that the transcendental entire function is real with only real zeros, and we prove the much stronger result that such a function has no orbits consisting of unbounded wandering domains whenever the order is less than 1. This raises the question as to whether such wandering domains can exist for any transcendental entire function with order less than 1. Key ingredients of our proofs are new results in classical complex analysis with wider applications. These new results concern: the winding properties of the images of certain curves proved using extremal length arguments, growth estimates for entire functions, and the distribution of the zeros of entire functions of order less than 1

    A sharp growth condition for a fast escaping spider's web

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    We show that the fast escaping set A(f)A(f) of a transcendental entire function ff has a structure known as a spider's web whenever the maximum modulus of ff grows below a certain rate. We give examples of entire functions for which the fast escaping set is not a spider's web which show that this growth rate is best possible. By our earlier results, these are the first examples for which the escaping set has a spider's web structure but the fast escaping set does not. These results give new insight into a conjecture of Baker and a conjecture of Eremenko

    Exotic Baker and wandering domains for Ahlfors islands maps

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    Let X be a Riemann surface of genus at most 1, i.e. X is the Riemann sphere or a torus. We construct a variety of examples of analytic functions g:W->X, where W is an arbitrary subdomain of X, that satisfy Epstein's "Ahlfors islands condition". In particular, we show that the accumulation set of any curve tending to the boundary of W can be realized as the omega-limit set of a Baker domain of such a function. As a corollary of our construction, we show that there are entire functions with Baker domains in which the iterates converge to infinity arbitrarily slowly. We also construct Ahlfors islands maps with wandering domains and logarithmic singularities, as well as examples where X is a compact hyperbolic surface.Comment: 18 page

    Permutable entire functions and multiply connected wandering domains

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    Let f and g be permutable transcendental entire functions. We use a recent analysis of the dynamical behaviour in multiply connected wandering domains to make progress on the long standing conjecture that the Julia sets of f and g are equal; in particular, we show that J(f)=J(g) provided that neither f nor g has a simply connected wandering domain in the fast escaping set

    An evaluation of properties related to wear time of four dressings during a five-day period

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    This study evaluated skin tolerance and other properties relating to wear time, such as conformability and comfort, pain on dressing removal, adhesion and premature detachment, of four advanced hydrated dressings applied to the knees and elbows of 22 healthy volunteers over a fixed five-day period. The dressings all incorporate silicone-based adhesives and are designed to provide a moist wound environment while managing exudate. Skin tolerance was good for all four dressings but there was variation in regards to wear time and fluid-handling properties. Conflict of interest: this work was supported by a grant from Mölnlycke Health Care, Swede

    Hyperbolic dimension of Julia sets of meromorphic maps with logarithmic tracts

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    We prove that for meromorphic maps with logarithmic tracts (e.g. entire or meromorphic maps with a finite number of poles from class B\mathcal B), the Julia set contains a compact invariant hyperbolic Cantor set of Hausdorff dimension greater than 1. Hence, the hyperbolic dimension of the Julia set is greater than 1.Comment: 7 pages, 1 figur
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