UnaryNodes

The number of nodes with exactly one child.

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UnaryNodes(tree)The number of nodes with exactly one child.

Typed signatures

Type	Package	Applies
(binary_tree | ordered_tree) -> number	combinatorics	always

Domain: Tree statistics

Details

• Defined over BinaryTree as an expression in _x, evaluated by compute-engine — the definition IS the implementation.
• Takes a BinaryTree and nothing else — it reads values against their positions, or walks the orbits, so it needs the bijection. Applying it to a bare list is a type error, not a wrong answer.

Definition

Epsil, as the implementation runs it.

on BinaryTree, over _x

Apply(
       Function(0 if t in Integers else ((0 if t[2] in Integers else 1) if t[1] in
                                                                           Integers else 1 if t[2] in Integers else 0) +
                                        self(self, t[1]) + self(self, t[2]), self, t),
       Function(0 if t in Integers else ((0 if t[2] in Integers else 1) if t[1] in
                                                                           Integers else 1 if t[2] in Integers else 0) +
                                        self(self, t[1]) + self(self, t[2]), self, t),
       _x,
     )

Examples

Basic #

the binary tree $[[.,.],[[.,.],.]]$

live ↗

In$\mathrm{UnaryNodes}({\operatorname{BinaryTree}}(\bigl\lbrack\bigl\lbrack0, 0\bigr\rbrack, \bigl\lbrack\bigl\lbrack0, 0\bigr\rbrack, 0\bigr\rbrack\bigr\rbrack))$Out$1$

the ordered tree $[[],[[]],[]]$: only the middle child has exactly one child

live ↗

In$\mathrm{CombinatorialStat}({\operatorname{OrderedTree}}(\bigl\lbrack\bigl\lbrack\bigr\rbrack, \bigl\lbrack\bigl\lbrack\bigr\rbrack\bigr\rbrack, \bigl\lbrack\bigr\rbrack\bigr\rbrack), \text{UnaryNodes})$Out$1$

Properties #

FindStat's value for [.,[.,.]]

live ↗

In$\mathrm{CombinatorialStat}({\operatorname{BinaryTree}}(\bigl\lbrack0, \bigl\lbrack0, 0\bigr\rbrack\bigr\rbrack), \text{UnaryNodes})$Out$1$

Known value · FindStat St000385

FindStat's value for [[.,.],.]

live ↗

In$\mathrm{CombinatorialStat}({\operatorname{BinaryTree}}(\bigl\lbrack\bigl\lbrack0, 0\bigr\rbrack, 0\bigr\rbrack), \text{UnaryNodes})$Out$1$

Known value · FindStat St000385

FindStat's value for [.,[.,[.,.]]]

live ↗

In$\mathrm{CombinatorialStat}({\operatorname{BinaryTree}}(\bigl\lbrack0, \bigl\lbrack0, \bigl\lbrack0, 0\bigr\rbrack\bigr\rbrack\bigr\rbrack), \text{UnaryNodes})$Out$2$

Known value · FindStat St000385

About

Examples	5
Crosswalk	FindStat