7 research outputs found

    Computation of Atomic Fibers of Z-Linear Maps

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    For given matrix A∈Zd×nA\in\Z^{d\times n}, the set Pb={z:Az=b,z∈Z+n}P_{b}=\{z:Az=b,z\in\Z^n_+\} describes the preimage or fiber of b∈Zdb\in\Z^d under the Z\Z-linear map fA:Z+n→Zdf_A:\Z^n_+\to\Z^d, x↦Axx\mapsto Ax. The fiber PbP_{b} is called atomic, if Pb=Pb1+Pb2P_{b}=P_{b_1}+P_{b_2} implies b=b1b=b_1 or b=b2b=b_2. In this paper we present a novel algorithm to compute such atomic fibers. An algorithmic solution to appearing subproblems, computational examples and applications are included as well.Comment: 27 page

    Computation of atomic fibers of Z-linear maps

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    For given matrix A∈Zd×nA\in\Z^{d\times n}, the set Pb={z:Az=b,z∈Z+n}P_{b}=\{z:Az=b,z\in\Z^n_+\} describes the preimage or fiber of b∈Zdb\in\Z^d under the Z\Z-linear map fA:Z+n→Zdf_A:\Z^n_+\rightarrow\Z^d, x↦Axx\mapsto Ax. The fiber PbP_{b} is called atomic, if Pb=Pb1+Pb2P_{b}=P_{b_1}+P_{b_2} implies b=b1b=b_1 or b=b2b=b_2. In this paper we present a novel algorithm to compute such atomic fibers. An algorithmic solution to appearing subproblems, computational examples and applications are included as well

    Finiteness theorems in stochastic integer programming

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    We study Graver test sets for families of linear multi-stage stochastic integer programs with varying number of scenarios. We show that these test sets can be decomposed into finitely many ``building blocks'', independent of the number of scenarios, and we give an effective procedure to compute these building blocks. The paper includes an introduction to Nash-Williams' theory of better-quasi-orderings, which is used to show termination of our algorithm. We also apply this theory to finiteness results for Hilbert functions.Comment: 36 p

    Computation of atomic fibers of Z-linear maps

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    For given matrix A∈Zd×nA\in\Z^{d\times n}, the set Pb={z:Az=b,z∈Z+n}P_{b}=\{z:Az=b,z\in\Z^n_+\} describes the preimage or fiber of b∈Zdb\in\Z^d under the Z\Z-linear map fA:Z+n→Zdf_A:\Z^n_+\rightarrow\Z^d, x↦Axx\mapsto Ax. The fiber PbP_{b} is called atomic, if Pb=Pb1+Pb2P_{b}=P_{b_1}+P_{b_2} implies b=b1b=b_1 or b=b2b=b_2. In this paper we present a novel algorithm to compute such atomic fibers. An algorithmic solution to appearing subproblems, computational examples and applications are included as well
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