WorldCat Identities

Fleischer, Lisa

Overview
Works: 6 works in 16 publications in 1 language and 31 library holdings
Roles: Author
Classifications: QA76.952, 330
Publication Timeline
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Most widely held works by Lisa Fleischer
A strongly polynomial-time algorithm for minimizing submodular functions by Satoru Iwata( Book )

6 editions published in 1999 in English and held by 11 WorldCat member libraries worldwide

Abstract: "This paper presents a combinatorial polynomial-time algorithm for minimizing submodular set functions. The algorithm employs a scaling scheme that uses a flow in the complete directed graph on the underlying set with each arc capacity equal to the scaled parameter. The resulting algorithm runs in time bounded by a polynomial in the size of the underlying set and the largest length of the function value. The paper also presents a strongly polynomial-time version that runs in time bounded by a polynomial in the size of the underlying set independent of the function value. These are the first combinatorial algorithms for submodular function minimization that run in (strongly) polynomial time."
A faster capacity scaling algorithm for minimum cost submodular flow by Lisa Fleischer( Book )

6 editions published in 1999 in English and held by 11 WorldCat member libraries worldwide

Abstract: "We describe an O(n⁴h min[log U, n² log n]) capacity scaling algorithm for the minimum cost submodular flow problem. Our algorithm modifies and extends the Edmonds-Karp capacity scaling algorithm for minimum cost flow to solve the minimum cost submodular flow problem. The modification entails scaling a relaxation parameter [delta]. Capacities are relaxed by attaching a complete directed graph with uniform arc capacity [delta] in each scaling phase. We then modify a feasible submodular flow by relaxing the submodular constraints, so that complementary slackness is satisfied. This creates discrepancies between the boundary of the flow and the base polytope of a relaxed submodular function. To reduce these discrepancies, we use a variant of the successive shortest path algorithm that augments flow along min cost paths of residual capacity at least [delta]. The shortest augmenting path subroutine we use is a variant of Dijkstra's algorithm modified to handle exchange capacity arcs efficiently. The result is a weakly polynomial time algorithm whose running time is better than any existing submodular flow algorithm when U is small and C is big. We also show how to use max mean cuts to make the algorithm strongly polynomial. The resulting algorithm is the first capacity scaling algorithm to match the current best strongly polynomial bound for submodular flow."
A divide-and-conquer algorithm for identifying strongly connectedcomponents( )

1 edition published in 2003 in English and held by 6 WorldCat member libraries worldwide

Strongly connected components of a directed graph can be found in an optimal linear time, by algorithms based on depth first search. Unfortunately, depth first search is difficult to parallelize. We describe two divide--and--conquer algorithms for this problem that have significantly greater potential for parallelization. We show the expected serial runtime of our simpler algorithm to be O(m log n), for a graph with n vertices and m edges. We then show that the second algorithm has O(mlog n) worst--case complexity
A strongly polynomial-time algorithm for minimizing submodular functions( )

1 edition published in 1999 in English and held by 1 WorldCat member library worldwide

A tight 4.67-approximation algorithm for the multi-commodity rent-or-buy problem( Book )

1 edition published in 2005 in English and held by 1 WorldCat member library worldwide

A faster capacity scaling algorithm for minimum cost submodular flow( )

1 edition published in 1999 in English and held by 1 WorldCat member library worldwide

 
Audience Level
0
Audience Level
1
  General Special  
Audience level: 0.82 (from 0.78 for A divide-a ... to 0.98 for A divide-a ...)

Alternative Names
Fleischer, L.

Languages
English (16)