A graph is a tree of paths (cycles), if its vertex set can be partitioned into clusters, such that each cluster induces a simple path (cycle), and the clusters form a tree. Our main result states that the problem whether or not a given graph is a tree of paths (cycles) is NP-complete. Moreover, if the length of the paths (cycles) is bounded by a constant, the problem is in P.

The tree and tour cover problems on an edge-weighted graph are to compute a minimum weight tree and closed walk, respectively, whose vertices form a vertex cover. Both problems are NP-hard. In this note we give strongly polynomial time, constant factor approximation algorithms for both problems. An interesting feature of our algorithms is how they combine approximations of other problems, namel...

A Study on the Mutation Rates of a Genetic Algorithm Interacting with a Sandpile p. 32 On the Design of Boolean Network Robots p. 43 EvoGames Contributions Multiple Tree for Partially Observable Monte-Carlo Tree Search p. 53 Evolving Interesting Maps for a First Person Shooter p. 63 Revisiting Monte-Carlo Tree Search on a Normal Form Game: NoGo p. 73 Nested Look-Ahead Evolutionary Algorithm Bas...

In Rogers (1997b) we introduced a new class of models, three-dimensional tree manifolds (3-TM), that can serve as both the derived and derivation structures for TAGs in the same way that trees serve as both derived and derivation structures for CFGs. These tree-manifolds are higher-dimensional analogs of trees; in a 3-TM the children of a node form an ordinary (two-dimensional) tree just as in ...

A form processing system aims to extract meaningful data from a form document for ooce automation 1, 2, 3]. The main interest is to extract user lled-in data which is considered to be meaningful. However, in order to perform such a task, the structure of the form should be known in advance. The form structure can be obtained by processing a blank model form on which no user lled-in data exists....

Symbolic transducers are useful in the context of web security as they form the foundation for sanitization of potentially malicious data. We define Symbolic Tree Transducers as a generalization of Regular Transducers as finite state input-output tree automata with logical constraints over a parametric background theory. We examine key closure properties of Symbolic Tree Transducers and we deve...

We provide strong theoretical and experimental evidence that standard sub-tree crossover with uniform selection of crossover points pushes a population of a-ary GP trees towards a distribution of tree sizes of the form: Pr{n} = (1− apa) ( an+ 1 n ) (1− pa) pa where n is the number of internal nodes in a tree and pa is a constant. This result generalises the result previously reported for the ca...

In this paper, we give a complete characterization of the existence of a galled-tree network in the form of simple sufficient and necessary conditions for both root-known and root-unknown cases. As a by-product we obtain a simple algorithm for constructing galled-tree networks. We also introduce a new necessary condition for the existence of a galled-tree network similar to bi-convexity.

A graph is a tree of paths (cycles), if its vertex set can be partitioned into clusters, such that each cluster induces a simple path (cycle), and the clusters form a tree. Our main result states that the problem whether or not a given graph is a tree of paths (cycles) is NP-complete. Moreover, if the length of the paths (cycles) is bounded by a constant, the problem is in P.

In this paper, we argue that in it-clefts as in It was Ohno who won, the cleft pronoun (it) and the cleft clause (who won) form a discontinuous syntactic constituent, and a semantic unit as a definite description, presenting arguments from Percus (1997) and Hedberg (2000). We propose a syntax of it-clefts using Tree-Local MultiComponent Tree Adjoining Grammar and a compositional semantics on th...