,
Benjamin Smith
,
Sebastian Wild
Creative Commons Attribution 4.0 International license
Finding schedules for pairwise meetings between the members of a complex social group without creating interpersonal conflict is challenging, especially when different relationships have different needs. We formally define and study the underlying optimisation problem: Polyamorous Scheduling. In Polyamorous Scheduling, we are given an edge-weighted graph and try to find a periodic schedule of matchings in this graph such that the maximal weighted waiting time between consecutive occurrences of the same edge is minimised. We show that the problem is NP-hard and that there is no efficient approximation algorithm with a better ratio than 4/3 unless P = NP. On the positive side, we obtain an O(log n)-approximation algorithm; indeed, an O(log Δ)-approximation for Δ the maximum degree, i.e., the largest number of relationships of any individual. We also define a generalisation of density from the Pinwheel Scheduling Problem, "poly density", and ask whether there exists a poly-density threshold similar to the 5/6-density threshold for Pinwheel Scheduling [Kawamura, STOC 2024]. Polyamorous Scheduling is a natural generalisation of Pinwheel Scheduling with respect to its optimisation variant, Bamboo Garden Trimming. Our work contributes the first nontrivial hardness-of-approximation reduction for any periodic scheduling problem, and opens up numerous avenues for further study of Polyamorous Scheduling.
@InProceedings{gasieniec_et_al:LIPIcs.FUN.2024.15,
author = {G\k{a}sieniec, Leszek and Smith, Benjamin and Wild, Sebastian},
title = {{Polyamorous Scheduling}},
booktitle = {12th International Conference on Fun with Algorithms (FUN 2024)},
pages = {15:1--15:18},
series = {Leibniz International Proceedings in Informatics (LIPIcs)},
ISBN = {978-3-95977-314-0},
ISSN = {1868-8969},
year = {2024},
volume = {291},
editor = {Broder, Andrei Z. and Tamir, Tami},
publisher = {Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
address = {Dagstuhl, Germany},
URL = {https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.FUN.2024.15},
URN = {urn:nbn:de:0030-drops-199234},
doi = {10.4230/LIPIcs.FUN.2024.15},
annote = {Keywords: Periodic scheduling, Pinwheel scheduling, Edge-coloring, Chromatic index, Approximation algorithms, Hardness of approximation}
}