A

An Open Pouring Problem

DROPS (Schloss Dagstuhl – Leibniz Center for Informatics)

Abstract

We analyze a little riddle that has challenged mathematicians for half a century. Imagine three clubs catering to people with some niche interest. Everyone willing to join a club has done so and nobody new will pick up this eccentric hobby for the foreseeable future, thus the mutually exclusive clubs compete for a common constituency. Members are highly invested in their chosen club; only a targeted campaign plus prolonged personal persuasion can convince them to consider switching. Even then, they will never be enticed into a bigger group as they naturally pride themselves in avoiding the mainstream. Therefore each club occasionally starts a campaign against a larger competitor and sends its own members out on a recommendation program. Each will win one person over; the small club can thus effectively double its own numbers at the larger one’s expense. Is there always a risk for one club to wind up with zero members, forcing it out of business? If so, how many campaign cycles will this take?

Authors 3

  1. ETH Zurich

    Affiliation as printed

    Department of Computer Science, ETH Zürich, Switzerland

    ETH Zurich, Zurich, Switzerland

  2. RWTH Aachen University

    Affiliation as printed

    Department of Computer Science, RWTH Aachen, Germany

    RWTH Aachen University, Aachen, Germany

  3. ETH Zurich

    Affiliation as printed

    Department of Computer Science, ETH Zürich, Switzerland

    ETH Zurich, Zurich, Switzerland

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