Host: The Japanese Society for Artificial intelligence
Name : 117th SIG-FPAI
Number : 117
Location : [in Japanese]
Date : September 29, 2021
Pages 02-
In decision tree learning, we split an instance space into two subspaces based on a of instances at each node. For numerical or ordinal categorical features, this can be done by an "optimal" hyperplane that separates the domain space of those features. For nominal categorical features, however, it is not obvious to define a "hyperplane" of the domain space. Lucena (Lucena, AISTAT 2020) pointed out that the domain space of nominal categorical features may be structured and exploited this structural information to learn decision trees. In this method, at each internal node, we need to find an "optimal" bipartition of a graph whose vertices are labeled by either +1 or ?1 such that both sides are connected and the misclassification is minimized. In this paper, we formalize this problem as Connected Bipartition and investigate its computational complexity.