Journal of Integer Sequences, Vol. 27 (2024), Article 24.4.2

Counting Bubbles in Linear Chord Diagrams


Donovan Young
St Albans
Hertfordshire AL3 4HB
United Kingdom

Abstract:

In a linear chord diagram, a short chord is one that joins adjacent vertices. We define a bubble to be a region in a linear chord diagram devoid of short chords. We derive a formal generating function counting bubbles by their size and find an exact result for the mean bubble size. We find that once one discards diagrams that have no short chords at all, the distribution of bubble sizes is given by a smooth function in the limit of long diagrams. Using a summation over short chords, we find the exact form of this asymptotic distribution.


Full version:  pdf,    dvi,    ps,    latex    


(Concerned with sequences A079267 A278990 A367000.)


Received November 6 2023; revised versions received December 18 2023; February 12 2024. Published in Journal of Integer Sequences, March 18 2024.


Return to Journal of Integer Sequences home page