Fig. 2
From: Locally epistatic models for genome-wide prediction and association by importance sampling
An example of a tree to rules. At each intermediate node, an observation goes to the left branch if and only if the condition shown there is satisfied. A simple regression tree which can be represented as \(y=20 I(M_1<0)(M_2<1)+15 I(M_1<0)I(M_2\ge 1)+10 I(M_1\ge 0).\) Each leaf node defines a rule which can be expressed as a product of indicator functions of half spaces. Each rule specifies a ‘simple’ rectangular region in the input space