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Reflexive modules on normal surface singularities and representations of the local fundamental group
We consider the Riemann-Hilbert correspondence on the complement of a normal surface singularity (X,x). Through a closure operation we obtain a correspondence between the category of finite dimensional representations of the local fundamental group and the category of left DX,x-modules that are reflexive as OX,x-modules. We show that under this correspondence profinite representations correspond to invariant modules and that these admit a canonical structure as left DX,x-modules. We prove that the fundamental module is an invariant module if and only if (X,x) is a quotient singularity. Finally we investigate some algebraisation aspects. 相似文献
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The front-tracking method for hyperbolic conservation laws is combined with operator splitting to study the shallow water equations. Furthermore, the method includes adaptive grid refinement in multidimensions and shock tracking in one dimension. The front-tracking method is unconditionally stable, but for practical computations feasible CFL numbers are moderately above unity (typically between 1 and 5). The method resolves shocks sharply and is highly efficient. The numerical technique is applied to four test cases, the first being an expanding bore with rotational symmetry. The second problem addresses the question of describing the time development of two constant water levels separated by a dam that breaks instantaneously. The third problem compares the front-tracking method with an explicit analytic solution of water waves rotating over a parabolic bottom profile. Finally, we study flow over an obstacle in one dimension. 相似文献
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A sample preparation device for microanalysis and trace analysis based on acoustic levitation is described. Derivatization
can be performed in a single levitated drop as part of the sample pretreatment in an analytical procedure. The applicability
of the experimental setup is demonstrated. First results of the preconcentration of hexachlorobenzene are given.
Received: 20 August 1999 / Accepted: 7 September 1999 相似文献
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A sample preparation device for microanalysis and trace analysis based on acoustic levitation is described. Derivatization can be performed in a single levitated drop as part of the sample pretreatment in an analytical procedure. The applicability of the experimental setup is demonstrated. First results of the preconcentration of hexachlorobenzene are given. 相似文献
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