Articles de revista
http://hdl.handle.net/2117/3517
2015-11-30T13:25:13ZNormal higher-order termination
http://hdl.handle.net/2117/79284
Normal higher-order termination
Jouannaud, Jean Pierre; Rubio Gimeno, Alberto
We extend the termination proof methods based on reduction orderings to higher-order rewriting systems based on higher-order pattern matching. We accommodate, on the one hand, a weakly polymorphic, algebraic extension of Church's simply typed λ-calculus and, on the other hand, any use of eta, as a reduction, as an expansion, or as an equation. The user's rules may be of any type in this type system, either a base, functional, or weakly polymorphic type.
2015-11-16T09:58:07ZJouannaud, Jean PierreRubio Gimeno, AlbertoWe extend the termination proof methods based on reduction orderings to higher-order rewriting systems based on higher-order pattern matching. We accommodate, on the one hand, a weakly polymorphic, algebraic extension of Church's simply typed λ-calculus and, on the other hand, any use of eta, as a reduction, as an expansion, or as an equation. The user's rules may be of any type in this type system, either a base, functional, or weakly polymorphic type.Efficiently calculating evolutionary tree measures using SAT
http://hdl.handle.net/2117/12674
Efficiently calculating evolutionary tree measures using SAT
Bonet Carbonell, M. Luisa; John, Katherine St.
We develop techniques to calculate important measures in evolutionary biology by encoding to CNF formulas and using powerful SAT solvers. Comparing evolutionary trees is a necessary step in tree reconstruction algorithms, locating recombination and lateral gene transfer, and in analyzing and visualizing sets of trees. We focus on two popular comparison measures for trees: the hybridization number and the rooted subtree-prune-and-regraft (rSPR) distance. Both have recently been shown to be NP-hard, and effcient algorithms are needed to compute
and approximate these measures. We encode these as a Boolean formula such that two trees have hybridization number k (or rSPR distance k) if and only if the corresponding formula is satisfiable. We use state-of-the-art SAT solvers to determine if the formula encoding the measure has a satisfying assignment. Our encoding also provides a rich
source of real-world SAT instances, and we include a comparison of several recent solvers (minisat, adaptg2wsat, novelty+p, Walksat, March KS and SATzilla).
2011-05-30T14:45:23ZBonet Carbonell, M. LuisaJohn, Katherine St.We develop techniques to calculate important measures in evolutionary biology by encoding to CNF formulas and using powerful SAT solvers. Comparing evolutionary trees is a necessary step in tree reconstruction algorithms, locating recombination and lateral gene transfer, and in analyzing and visualizing sets of trees. We focus on two popular comparison measures for trees: the hybridization number and the rooted subtree-prune-and-regraft (rSPR) distance. Both have recently been shown to be NP-hard, and effcient algorithms are needed to compute
and approximate these measures. We encode these as a Boolean formula such that two trees have hybridization number k (or rSPR distance k) if and only if the corresponding formula is satisfiable. We use state-of-the-art SAT solvers to determine if the formula encoding the measure has a satisfying assignment. Our encoding also provides a rich
source of real-world SAT instances, and we include a comparison of several recent solvers (minisat, adaptg2wsat, novelty+p, Walksat, March KS and SATzilla).Mining frequent closed rooted trees
http://hdl.handle.net/2117/6835
Mining frequent closed rooted trees
Balcázar Navarro, José Luis; Bifet Figuerol, Albert Carles; Lozano Bojados, Antoni
Many knowledge representation mechanisms are based on tree-like structures, thus symbolizing the fact that certain pieces of information are related in one sense or another. There exists a well-studied process of closure-based data mining in the itemset framework: we consider the extension of this process into trees. We focus mostly on the case where labels on the nodes are nonexistent or unreliable, and discuss algorithms for closurebased mining that only rely on the root of the tree and the link structure.
We provide a notion of intersection that leads to a deeper understanding of the notion of support-based closure, in terms of an actual closure operator.
We describe combinatorial characterizations and some properties of ordered trees, discuss their applicability to unordered trees, and rely on them to design efficient algorithms for mining frequent closed subtrees both in the ordered and the unordered settings. Empirical validations and comparisons with alternative algorithms are provided.
2010-03-30T09:00:52ZBalcázar Navarro, José LuisBifet Figuerol, Albert CarlesLozano Bojados, AntoniMany knowledge representation mechanisms are based on tree-like structures, thus symbolizing the fact that certain pieces of information are related in one sense or another. There exists a well-studied process of closure-based data mining in the itemset framework: we consider the extension of this process into trees. We focus mostly on the case where labels on the nodes are nonexistent or unreliable, and discuss algorithms for closurebased mining that only rely on the root of the tree and the link structure.
We provide a notion of intersection that leads to a deeper understanding of the notion of support-based closure, in terms of an actual closure operator.
We describe combinatorial characterizations and some properties of ordered trees, discuss their applicability to unordered trees, and rely on them to design efficient algorithms for mining frequent closed subtrees both in the ordered and the unordered settings. Empirical validations and comparisons with alternative algorithms are provided.