DescentWord

Letter i is 1 when the word falls between positions i and i + 1: the descent set as a binary word.

FindStatMp00109via Permutation↗

DescentWord(Permutation)Letter i is 1 when the word falls between positions i and i + 1: the descent set as a binary word.

Typed signatures

Type	Package	Applies
(permutation) -> binary_word	combinatorics	always

Domain: Combinatorial maps

Details

• Takes a Permutation and returns a BinaryWord — a typed map, so a wrong carrier is a type error rather than a wrong answer.
• One letter shorter than the permutation, so the empty permutation has no descent word.

Examples

Basic #

the one-line word $231$

live ↗

In$\mathrm{DescentWord}({\operatorname{Permutation}}([2, 3, 1]))$Out${\operatorname{BinaryWord}}([0, 1])$

About

Examples	1
Crosswalk	FindStat