ACGO

SUPERSET: A (super)natural variant of the card game SET

Event Date: Apr 04, 2018 in ACGO, Seminars

Abstract: We consider SUPERSET, a lesser-known but interesting variant of the famous card game SET. Here, players look for SUPERSETs instead of SETs, that is, the symmetric difference of two SETs that intersect in exactly one card. In this paper, we pose questions that have been previously posed for SET and provide answers to them; we also show relations between SET and SUPERSET. For the regular deck of cards, which can be identified with F_3^4, we give an elegant proof for the fact that the maximum number of cards that can be on the table without having a SUPERSET is 9, solving an open...

An open problem on matchings

Event Date: Apr 11, 2018 in ACGO, Seminars

The long-term behaviour of a queue-based dynamic traffic model

Event Date: Apr 16, 2018 in ACGO, Seminars

Abstract: The fluid queueing model, introduced by Vickrey in ’69, is probably the simplest model that plausibly captures the notion of time-varying flows. Although the model is quite simple, our current theoretical understanding of equilibrium behaviour in this model is rather limited, and many fundamental questions remain open. I will discuss the resolution of a deceptively simple-sounding problem: do queue lengths remain bounded in the equilibria under natural necessary conditions? (Joint work with Roberto Cominetti and José Correa)

Lower Bounds for Online Matching on the Line

Event Date: Apr 25, 2018 in ACGO, Seminars

Abstract: In the online matching on the line problem, the task is to match a set of requests R online to a given set of servers S. The distance metric between any two points in R ∪ S is a line metric and the objective for the online algorithm is to minimize the sum of distances between matched server-request pairs. This problem is well-studied and – despite recent improvements – there is still a large gap between the best known lower and upper bounds: The best known deterministic algorithm for the problem is O(log^2(n))-competitive, while the best known deterministic lower bound is 9 .001....

Adaptive Computation of Frechet Distance: Upper and Conditional Lower Bound

Event Date: May 09, 2018 in ACGO, Seminars

Abstract: The Fréchet distance is a measure of similarity between curves that takes into account the location and ordering of the points along the curves, and permits to abstract, among other things, differences of resolution between the two curves (with application to morphing, handwriting recognition and protein structure alignment, among others). In 1991, Art and Godau introdued this measure to Computational Geometry, describing an algorithm computing the Fréchet distance between two polygonal curves composed of $n$ and $m$ segments respectively in time within $O(mn\log(mn))$, the first...