In this paper, we propose a metric for measuring the complexity of a DTD. For the same purpose, different designers may create different DTDs. A complexity metric can assist us to evaluate and compare their different merits. Through the recognition of strongly connected components, the metric accommodates the recursive relationship of elements in a DTD. The metric presented here can be expresse...

We show that the problems of deciding whether an ordered set has at least k depth-first linear extensions and whether an ordered set has at least k greedy linear extensions are NP-hard. AMS subject chssi6catiom (1980). 06A10, 68C25.

We consider the problem of minimizing depth-first search effort for the generation of all solutions to a problem stated as a conjunction of subproblems. For a sequence of subproblems that share no variables, the effort is minimized by ordering the subproblems in decreasing ratio of NC/(N 1), where N and C are the number of solutions and the search effort of obtaining a solution to the subproble...

Motivated by a problem of targeted advertising in social networks, we introduce and study a new model of online learning on labeled graphs where the graph is initially unknown, and the algorithm is free to choose the next vertex to predict. After observing that natural nonadaptive exploration/prediction strategies (like depth-first with majority vote) badly fail on simple binary labeled graphs,...

In most cases game programs have to decide their next move under strict time constraints Iterative deepening is the most common method to make sure a move is played that is the result of a completed search to a certain depth To produce a reasonable move at each iteration a combination of pruning techniques and search extensions is used Often the decisions for pruning and extending the search ar...

Thomsen’s λ search and Nagai’s depth-first proofnumber (DFPN) search are two powerful but very different AND/OR tree search algorithms. Lambda Depth-First Proof Number search (LDFPN) is a novel algorithm that combines ideas from both algorithms. λ search can dramatically reduce a search space by finding different levels of threat sequences. DFPN employs the notion of proof and disproof numbers ...

After PN search was developed and had achieved many successes for solving some hard problems, innovations to depth-first search algorithms were based on the idea of proof numbers. This article introduces two such innovative algorithms: PN* and PDS. The PN* algorithm was developed for solving Tsume-Shogi problems, among which one with more than 1500 steps. Then, PDS was proposed to strengthen th...

An extention of the alpha-beta tree priming strategy to game trees with "probability" nodes, whose values are defined as the (possibly weighted) average of their successors' values, is developed. These '*-minhnax' trees pertain to games involving chance but no concealed infornzation. Based upon our search strategy, )re formulate and then analyze several algorithnzs for *-minimax trees. An initi...