Extended Thermography for Multiple Kos in Go

Abstract

In evaluating a local position in go, players want to know its current territorial count and the value of a local play. Many go positions are combinatorial games; the mean value of the game corresponds to the count and its temperature corresponds to the value of the play. Thermography finds the mean value and temperature of a combinatorial game. However, go positions often include kos, repetitive positions which are not classical combinatorial games. Thermography has been generalized to include positions containing a single ko. This paper extends thermography further to include positions with multiple kos. It also introduces a method for pruning redundant branches of the game tree.