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  Maximizing concave functions in fixed dimension (1993) [12 citations — 0 self]

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by Edith Cohen, Nimrod Megiddo
in: Complexity in Numeric Computation
http://theory.stanford.edu/%7Emegiddo/pdf/opt_book.pdf
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Abstract:

In [3, 5, 2] the authors introduced a technique which enabled them to solve the parametric minimum cycle problem with a xed number of parameters in strongly polynomial time. In the current paper 1 we present this technique as a general tool. In order to allow for an independent reading of this paper, we repeat some of the de nitions and propositions given in [3, 5, 2]. Some proofs are not repeated, however, and instead we supply the interested reader with appropriate pointers. Suppose Q R d is a convex set given as an intersection of k halfspaces, and let g: Q!R be a concave function that is computable by a piecewise a ne algorithm (i.e., roughly, an algorithm that performs only multiplications by scalars, additions, and comparisons of intermediate values which depend on the input). Assume that such an algorithm A is given and the maximal number of operations required by A on any input (i.e., point inQ) is T. We show that under these assumptions, for any xedd, the function g can be maximized in a number of operations polynomial in k and T.We also present a general framework for parametric extensions of problems where this technique can be used to obtain strongly polynomial algorithms. Norton, Plotkin, and Tardos [12] applied a similar scheme and presented additional applications. Keywords: Complexity, concave-cost network ow, capacitated, global optimization, local optimization. 1 See [4, 2] for an earlier version. 1 1.

Citations

167 Linear programming in linear time when the dimension is fixed – Megiddo - 1984
54 On a multidimensional search technique and its application to the Euclidean one-center problem – Dyer - 1986
31 Towards a genuinely polynomial algorithm for linear programming – Megiddo - 1983
23 Improved algorithms for linear inequalities with two variables per inequality – Cohen, Megiddo - 1994
15 Using separation algorithms in fixed dimension – Norton, Plotkin - 1992
14 Linear programming – Clarkson - 1986
5 Combinatorial Algorithms for Optimization Problems – Cohen - 1991
5 Linear programming with two variables per inequality in poly log time – Lueker, Megiddo, et al. - 1990
3 Linear programming in O(n \Theta 3 d ) time – Clarkson - 1986
3 Strongly polynomial time and NC algorithms for detecting cycles in periodic graphs – Cohen, Megiddo - 1990
3 Complexity analysis and algorithms for some flow problems – Cohen, Megiddo - 1991
3 Using separation algorithms in xed dimensions – Norton, Plotkin, et al. - 1992
2 Maximizing concave functions in xed dimension – Cohen, Megiddo - 1990
1 Strongly polynomial and NC algorithms for detecting cycles in dynamic graphs – Cohen, Megiddo - 1989
1 Complexity analysis and algorithms for some ow problems – Cohen, Megiddo - 1991