Ranked Schröder Trees

Olivier Bodini (1) , Antoine Genitrini (2) , Mehdi Naima (1)

1 LIPN - Laboratoire d'Informatique de Paris-Nord
2 APR - Algorithmes, Programmes et Résolution

In biology, a phylogenetic tree is a tool to represent the evolutionary relationship between species. Unfortunately, the classical Schröder tree model is not adapted to take into account the chronology between the branching nodes. In particular, it does not answer the question: how many different phylogenetic stories lead to the creation of n species and what is the average time to get there? In this paper, we enrich this model in two distinct ways in order to obtain two ranked tree models for phylogenetics, i.e. models coding chronology. For that purpose, we first develop a model of (strongly) increasing Schröder trees, symbolically described in the classical context of increasing labeling trees. Then we introduce a generalization for the labeling with some unusual order constraint in Analytic Combinatorics (namely the weakly increasing trees). Although these models are direct extensions of the Schröder tree model, it appears that they are also in one-to-one correspondence with several classical combinatorial objects. Through the paper, we present these links, exhibit some parameters in typical large trees and conclude the studies with efficient uniform samplers.

Domaines: Algorithme et structure de données [cs.DS]; Combinatoire [math.CO]

Olivier Bodini, Antoine Genitrini, Mehdi Naima. Ranked Schröder Trees. ANALCO 2019 - 16th Workshop on Analytic Algorithmics and Combinatorics, Jan 2019, San Diego, CA, United States. pp.13-26, ⟨10.1137/1.9781611975505.2⟩. ⟨hal-02073631⟩