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VERSION:2.0
PRODID:-//University of Liverpool Computer Science Seminar System//v2//EN
BEGIN:VEVENT
DTSTAMP:20260913T162614Z
UID:Seminar-dept-1246@lxserverM.csc.liv.ac.uk
ORGANIZER:CN=Lutz Oettershagen:MAILTO:Lutz.Oettershagen@liverpool.ac.uk
DTSTART:20241029T130000
DTEND:20241029T140000
SUMMARY:School Seminar Series
DESCRIPTION:Aris Filos-Ratsikas: Pushing the Frontier on Approximate EFX Allocations \n\nWe study the problem of allocating a set of indivisible goods to a set of agents with additive valuation functions, aiming to achieve approximate envy-freeness up to any good (α-EFX). The state-of-the-art results on the problem include that (exact) EFX allocations exist when (a) there are at most three agents, or (b) the agents' valuation functions can take at most two values, or (c) the agents' valuation functions can be represented via a graph. For α-EFX, it is known that a 0.618-EFX allocation exists for any number of agents with additive valuation functions. In this work we show that 2/3-EFX allocations exist when (a) there are at most seven agents, (b) the agents' valuation functions can take at most three values, or (c) the agents' valuation functions can be represented via a multigraph. Our results can be interpreted in two ways. First, by relaxing the notion of EFX to 2/3-EFX, we obtain existence results for strict generalizations of the settings for which exact EFX allocations are known to exist. Secondly, by imposing restrictions on the setting, we manage to beat the barrier of 0.618 and achieve an approximation guarantee of 2/3. Therefore, our results push the frontier of existence and computation of approximate EFX allocations, and provide insights into the challenges of settling the existence of exact EFX allocations.\n\nhttps://www.csc.liv.ac.uk/research/seminars/abstract.php?id=1246
LOCATION:Ashton Lecture Theatre
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