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Iterative Plan Construction for the Workflow Satisfiability Problem
TLDR
A novel approach to the WSP, using techniques from CSP, has enabled a generic algorithm which is FPT for several families of workflow constraints considered in the literature, and it is proved that the union of FPT languages remains FPT if they satisfy a simple compatibility condition.
Maximum balanced subgraph problem parameterized above lower bound
TLDR
The following parameterized problem is considered: given a connected signed graph G with n vertices and m edges, decide whether G has a balanced subgraph with at least m2+n-14+k4 edges, where k is the parameter and an algorithm is obtained for the problem of runtime 8^k(kn)^O^(^1^).
Rearrangement moves on rooted phylogenetic networks
TLDR
This paper proposes “horizontal” moves that ensure that every network of a certain complexity can be reached from any other network of the same complexity, and “vertical” Moves that ensure reachability between networks of different complexities that are robust to the fact that networks with higher complexity usually allow a better fit with the data.
On the Workflow Satisfiability Problem with Class-Independent Constraints for Hierarchical Organizations
TLDR
It is proved that WSP is fixed-parameter tractable (FPT) for class-independent constraints defined over nested equivalence relations and developed an FPT algorithm to solve WSP instances incorporating such constraints.
Rooting for phylogenetic networks
TLDR
It is shown that, in general, it is NP-hard to decide whether an undirected network can be oriented as a tree-based network.
A Practical Fixed-Parameter Algorithm for Constructing Tree-Child Networks from Multiple Binary Trees
We present the first fixed-parameter algorithm for constructing a tree-child phylogenetic network that displays an arbitrary number of binary input trees and has the minimum number of reticulations
Kernels for below-upper-bound parameterizations of the hitting set and directed dominating set problems
TLDR
It is proved that Nonblocker has a linear-order kernel, and the degeneracy of the hypergraph H=(V,F), makes the problem not only fixed-parameter tractable, but also one with a linear kernel.
Systems of Linear Equations over F2 and Problems Parameterized above Average
TLDR
It is proved that for each fixed r≥2, Max r-Lin AA and Max Exact r-SAT AA can be solved in time 2O(k logk)+mO(1), and a tight lower bound on the maxima of pseudo-boolean functions is obtained.
Parameterized Complexity of Directed Steiner Tree on Sparse Graphs
TLDR
The undirected Steiner Tree problem becomes FPT when restricted to sparse classes of graphs such as planar graph, but the techniques used to show this result break down on directed planar graphs.
Algorithms for the workflow satisfiability problem engineered for counting constraints
TLDR
This paper describes an efficient implementation of an FPT algorithm for solving this subclass of the WSP and provides a reduction from a WSP instance to a pseudo-Boolean (PB) SAT instance.
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