Dennis M. Breuker

Solving 8 × 8 domineering

Abstract So far the game of Domineering has mainly been investigated by combinatorial-games researchers. Yet, it is a genuine two-player zero-sum game with perfect information, of which the general formulation is a topic of AI research. In that domain, many techniques have been developed for two-person games, especially for chess. In this article we show that one such technique, i.e., transposition tables, is fit for solving standard Domineering (i.e., on an 8×8 board). The game turns out to be a win for the player first to move. This result coincides with a result obtained independently by Morita Kazuro. Moreover, the technique of transposition tables is also applied to differently sized m×n boards, m ranging from 2 to 8, and n from m to 9. The results are given in tabular form. Finally, some conclusions on replacement schemes are drawn. In an appendix an analysis of four tournament games is provided.

A solution to the GHI problem for best-first search

In a search graph a node’s value may be dependent on the path leading to it. Different paths may lead to different values. Hence, it is difficult to determine the value of any node unambiguously. The problem is known as the graph-history-interaction (GHI) problem. This paper provides a solution for best-first search. First, we give a precise formulation of the problem. Then, for best-first search and for other searches, we review earlier proposals to overcome the problem. Next, our solution is given in detail. Here we introduce the notion of twin nodes, enabling a distinction of nodes according to their history. The implementation, called BTA (Base-Twin Algorithm), is performed for pn search, a best-first search algorithm. It is generally applicable to other best-first search algorithms. Experimental results in the field of computer chess confirm the claim that the GHI problem has been solved for best-first search.

A Solution to the GHI Problem for Best-First Search

In a search graph a nodes value may be dependent on the path leading to it. Different paths may lead to different values. Hence, it is difficult to determine the value of any node unambiguously. The problem is known as the graph-history-interaction (GHI) problem. This paper provides a solution for best-first search. First, we give a precise formulation of the problem. Then, for best-first search and for other searches, we review earlier proposals to overcome the problem. Next, our solution is given in detail. Here we introduce the notion of twin nodes, enabling a distinction of nodes according to their history. The implementation, called BTA (Base-Twin Algorithm), is performed for pn search, a best-first search algorithm. It is generally applicable to other best-first search algorithms. Experimental results in the field of computer chess confirm the claim that the GHI problem has been solved for best-first search.