36 research outputs found

    On sub-determinants and the diameter of polyhedra

    Full text link
    We derive a new upper bound on the diameter of a polyhedron P = {x \in R^n : Ax <= b}, where A \in Z^{m\timesn}. The bound is polynomial in n and the largest absolute value of a sub-determinant of A, denoted by \Delta. More precisely, we show that the diameter of P is bounded by O(\Delta^2 n^4 log n\Delta). If P is bounded, then we show that the diameter of P is at most O(\Delta^2 n^3.5 log n\Delta). For the special case in which A is a totally unimodular matrix, the bounds are O(n^4 log n) and O(n^3.5 log n) respectively. This improves over the previous best bound of O(m^16 n^3 (log mn)^3) due to Dyer and Frieze

    On Sub-determinants and the Diameter of Polyhedra

    Get PDF
    We derive a new upper bound on the diameter of a polyhedron P={xRn:Axb}P = \{x {\in } {\mathbb {R}}^n :Ax\le b\} P = { x ∈ R n : A x ≤ b } , where AZm×nA \in {\mathbb {Z}}^{m\times n} A ∈ Z m × n . The bound is polynomial in nn n and the largest absolute value of a sub-determinant of AA A , denoted by Δ\Delta Δ . More precisely, we show that the diameter of PP P is bounded by O(Δ2n4lognΔ)O(\Delta ^2 n^4\log n\Delta ) O ( Δ 2 n 4 log n Δ ) . If PP P is bounded, then we show that the diameter of PP P is at most O(Δ2n3.5lognΔ)O(\Delta ^2 n^{3.5}\log n\Delta ) O ( Δ 2 n 3.5 log n Δ ) . For the special case in which AA A is a totally unimodular matrix, the bounds are O(n4logn)O(n^4\log n) O ( n 4 log n ) and O(n3.5logn)O(n^{3.5}\log n) O ( n 3.5 log n ) respectively. This improves over the previous best bound of O(m16n3(logmn)3)O(m^{16}n^3(\log mn)^3) O ( m 16 n 3 ( log m n ) 3 ) due to Dyer and Frieze (Math Program 64:1-16, 1994)

    A Note on Non-Degenerate Integer Programs with Small Sub-Determinants

    Full text link
    The intention of this note is two-fold. First, we study integer optimization problems in standard form defined by AZm×nA \in\mathbb{Z}^{m\times{}n} and present an algorithm to solve such problems in polynomial-time provided that both the largest absolute value of an entry in AA and mm are constant. Then, this is applied to solve integer programs in inequality form in polynomial-time, where the absolute values of all maximal sub-determinants of AA lie between 11 and a constant

    Primitive Zonotopes

    Full text link
    We introduce and study a family of polytopes which can be seen as a generalization of the permutahedron of type BdB_d. We highlight connections with the largest possible diameter of the convex hull of a set of points in dimension dd whose coordinates are integers between 00 and kk, and with the computational complexity of multicriteria matroid optimization.Comment: The title was slightly modified, and the determination of the computational complexity of multicriteria matroid optimization was adde

    FPT-algorithms for some problems related to integer programming

    Full text link
    In this paper, we present FPT-algorithms for special cases of the shortest lattice vector, integer linear programming, and simplex width computation problems, when matrices included in the problems' formulations are near square. The parameter is the maximum absolute value of rank minors of the corresponding matrices. Additionally, we present FPT-algorithms with respect to the same parameter for the problems, when the matrices have no singular rank sub-matrices.Comment: arXiv admin note: text overlap with arXiv:1710.00321 From author: some minor corrections has been don
    corecore