# Reconstructing phylogenetic trees from multipartite quartet systems

## TL;DR

This paper introduces polynomial-time algorithms for reconstructing phylogenetic trees from specific multipartite quartet systems, advancing the computational methods for assembling evolutionary histories from small trees.

## Contribution

It defines new classes of quartet systems and provides the first polynomial-time algorithms for the Quartet Compatibility problem within these classes.

## Key findings

- Polynomial-time algorithms for complete multipartite quartet systems
- Polynomial-time algorithms for full multipartite quartet systems
- Enhanced methods for assembling phylogenetic trees from small quartets

## Abstract

A phylogenetic tree is a graphical representation of an evolutionary history of taxa in which the leaves correspond to the taxa and the non-leaves correspond to speciations. One of important problems in phylogenetic analysis is to assemble a global phylogenetic tree from small phylogenetic trees, particularly, quartet trees. {\sc Quartet Compatibility} is the problem of deciding whether there is a phylogenetic tree inducing a given collection of quartet trees, and to construct such a phylogenetic tree if it exists. It is known that {\sc Quartet Compatibility} is NP-hard and that there are only a few results known for polynomial-time solvable subclasses. In this paper, we introduce two novel classes of quartet systems, called complete multipartite quartet system and full multipartite quartet system, and present polynomial-time algorithms for {\sc Quartet Compatibility} for these systems.