text: export default (`
  # Binary Tree
  ## Introduction
  A [binary tree](https://en.wikipedia.org/wiki/Binary_tree) is a tree data structure in which each node has at most two children, which are referred to as the left child and the right child. A recursive definition using just set theory notions is that a (non-empty) binary tree is a tuple (L, S, R), where L and R are binary trees or the empty set and S is a singleton set.[1] Some authors allow the binary tree to be the empty set as well
  `)