Describing the problem - Tree Example

Defining the new breaks for \(X^1\) based on the tree model.

tree_x1_breaks <-
  tree:::labels.tree(tree_model) |>
  grep(pattern = "^x1", value = TRUE) |> 
  sub(pattern = "x1 (<|>) ", replacement = "") |> 
  as.double() |>
  unique() |>
  c(0, a = _ ,1) |>
  unname()

round(tree_x1_breaks, 2)

## [1] 0.00 0.18 0.60 1.00