Call for Invited Talk Nominations: HALG 2020

5th Highlights of Algorithms conference (HALG 2020)

ETH Zurich, June 3-5, 2020

http://2020.highlightsofalgorithms.org/

The HALG 2020 conference seeks high-quality nominations for invited talks that will highlight recent advances in algorithmic research. Similarly to previous years, there are two categories of invited talks:

A. survey (60 minutes): a survey of an algorithmic topic that has seen exciting developments in last couple of years.

B. paper (30 minutes): a significant algorithmic result appearing in a paper in 2019 or later.

To nominate, please email halg2020.nominations@gmail.com the following information:

  1. Basic details: speaker name + topic (for survey talk) or paper’s title, authors, conference/arxiv + preferable speaker (for paper talk).
  2. Brief justification: Focus on the benefits to the audience, e.g., quality of results, importance/relevance of topic, clarity of talk, speaker’s presentation skills.

All nominations will be reviewed by the Program Committee (PC) to select speakers that will be invited to the conference.

Nominations deadline: December 20, 2020 (for full consideration).

Call for Participation: HALG 2019 (Highlights of Algorithms)

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4rd Highlights of Algorithms conference (HALG 2019)
Copenhagen, June 14-16, 2019
http://highlightsofalgorithms.org/

The Highlights of Algorithms conference is a forum for presenting the
highlights of recent developments in algorithms and for discussing
potential further advances in this area. The conference will provide a
broad picture of the latest research in algorithms through a series of
invited talks, as well as the possibility for all researchers and
students to present their recent results through a series of short
talks and poster presentations. Attending the Highlights of Algorithms
conference will also be an opportunity for networking and meeting
leading researchers in algorithms.
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PROGRAM

The conference will begin on Friday, June 14, at 9:00 and end on
Sunday, June 16, at 18:00. A detailed schedule and a list of all
accepted short contributions can be found at:
2018.highlightsofalgorithms.org/programme.

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REGISTRATION

Please register on our webpage
     http://highlightsofalgorithms.org/registration
We have done our best to keep registration fees at a minimum:

Early registration (by April 29, 2019)
- academic rate (incl. postdocs): 160€
- student rate: 115€

Regular registration will be 50€ more expensive.

The organizers strongly recommend that you book your hotel as soon as possible.

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CONFERENCE VENUE

The conference will take place at the H.C. Ørsted Institute of the
University of Copenhagen.
The address is: Universitetsparken 5, DK-2100 Copenhagen.

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INVITED SPEAKERS

Survey speakers:
Monika Henzinger (University of Vienna)
Thomas Vidick (California Institute of Technology)
Laszlo Vegh (London School of Economics)
James Lee (University of Washington)
Timothy Chan (University of Illinois at Urbana-Champaign)
Sergei Vassilvitskii (Google, New York)

Invited talks:
Martin Grohe (RWTH Aachen University)
Josh Alman (MIT)
Nima Anari (Stanford University)
Michal Koucký (Charles University)
Naveen Garg (IIT Delhi)
Vera Traub (University of Bonn)
Rico Zenklusen (ETH Zurich)
Shayan Oveis Gharan (University of Washington)
Greg Bodwin (MIT)
Cliff Stein (Columbia University)
Sungjin Im (University of California at Merced)
C. Seshadhriy (University of California, Santa Cruz)
Shay Moran (Technion)
Bundit Laekhanukit (Shanghai University of Finance and Economics)
Sebastien Bubeck (Microsoft Research, Redmond)
Sushant Sachdeva (University of Toronto)
Kunal Talwar (Google Brain)
Moses Charikar (Stanford University)
Shuichi Hirahara (University of Tokyo)

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The Curse of Euclidean Metric: Square Roots

The Curse of Metric Island

The deadline was approaching without mercy and there was, of course, still some polishing to be done for our SODA paper. But then we run into an issue. To make things worse, this issue turned out to be a hard one, a fundamental known open problem in computational geometry. The good thing is, I liked the problem so much that I decided to dedicate it this post. This is the story about the Sum of Square Roots problem and how we bypassed (ignored) it without solving it.

Everything began in the haze of the 70's of the last millennium. It is nebulous who stumbled first upon this enigma. Some say that Ron Graham has discussed the problem in public lectures, some others say that Joseph O'Rourke has posed it as an open question in the American Mathematical Monthly, while some others suspect that the problem had been already hiding in older different formulations. However, it is a historical fact that one shinny/cloudy day, three computer scientists finished polishing a manuscript that became a classical paper known as "Some NP-complete geometric problems". In this paper, Michael Garey, Ron Graham and David Johnson showed the NP-hardness of two important problems in geometric metrics: Steiner Tree and Traveling Salesman. For the Euclidean plane, they showed only NP-hardness as they did not manage to show that these problems are contained in NP. Moreover, they accentuated that we cannot even rule out that the decision version of Euclidean Minimum Spanning Tree is outside of NP. What a seeming paradox given that we can compute such a minimum tree in polynomial time! So, whom did they blame? The short answer: The Euclidean metric. Garey and his coauthors explain that all these problems have a common hidden issue: They rely on comparing Euclidean lengths, that is, they rely on comparing irrational numbers based on square roots. Whereas this task is trivial if we just want to compare two line segments (e.g. by comparing the radicands), the problem starts when we want to compare two polygonal paths. Even assuming rational (or, after scaling, integer) coordinates, this problem translates into a question that is fundamental in computational geometry: Given two lists of integers, a1 ... and b1 ..., can we decide whether "∑ √ai ≥ ∑ √bi" in P? Put into words: Can we efficiently compare two sums of square roots over integers?

Continue reading

How to identify m numbers using m/log m checks

Here's an old trick that we found useful for proving some tight complexity lower bounds. You are given m coins, each of weight either a or b, and a modern scale that can tell you the total weight of any chosen subset of coins. How many weighings do you need to identify which coin is which? Checking each coin individually uses m weighings, but can you do less? In any weighing, we try some unknown number of weight-a coins between 0 and m, so this results in one of m + 1 possible values, giving us at most log(m + 1) bits of information. In total we need m bits of information to identify each coin, so clearly we will need at least Ω(m / log m) weighings. It turns out that this many is in fact enough, and this generalizes to various other settings with less restricted weights. This is the basis for two of our recent results: a tight complexity lower bound for Integer Linear Programming with few constraints and for multicoloring (a.k.a. b-fold coloring), assuming the Exponential Time Hypothesis. The trick allows us to use constraints that check the value of some number between 0 and m to indeed extract about log(m) bits of new information from each, in a way that is general enough to check m clauses of a 3-CNF-SAT instance using only O(m / log m) constraints. Continue reading

HALG 2019 - Call For Submissions of Short Contributed Presentations

The HALG 2019 conference seeks submissions for contributed presentations. Each presentation is expected to consist of a poster and a short talk (an invitation to the poster). There will be no conference proceedings, hence presenting work already published at a different venue or journal (or to be submitted there) is welcome.

If you would like to present your results at HALG 2019, please submit their details the abstract of the talk or the contribution of the poster via EasyChair: https://easychair.org/conferences/?conf=halg2019

The abstract should include (when relevant) information where the results have been published/accepted (e.g., conference), and where they are publicly available (e.g., arXiv). All submissions will be reviewed by the program committee, giving priority to new work not formally published yet, and to papers published in 2018 or later.

Submissions deadline: March 15th, 2019.
Late submissions will be accepted subject to space constraints.

Prophet inequality and auction design

Suppose you want to sell a car and there are 10 agents willing to buy it. You are not sure how much they could pay but for each of them you know a probability distribution of how high the offer will be. For example, a car salon would always pay 10K  but some person might offer 5K or 15K with equal probability. The best you could do is to first negotiate with all of them and then pick the highest bid. Unfortunately, you cannot do so - after seeing each offer you must irrevocably choose either to sell the car or to refuse the offer. What is the best strategy to maximize your revenue in this case?

In turns out that this is a well-studied optimization problem with a simple strategy that guarantees you can (on expectation) earn at least half as much as a hypothetical prophet, who knows all the bids in advance. This result is known as the prophet inequality. What is more surprising, this strategy would work even if you are a car retailer and want to sell five cars. Moreover, you might want to have some constraints, for example you do not want to sell two cars to buyers from the same city, or have multiple kinds of cars with different evaluations, and you can always guarantee an expected revenue comparable to the one of the prophets.

This problem not only exploits beautiful math but also has important applications in internet ad display. Actually, whenever you type a query into a web search engine, the ad system performs this kind of car-selling game with the ad suppliers, who offer different bids for their ad to be displayed to you.

Here is a link to our recent work with new developments in this theory: http://ieee-focs.org/FOCS-2018-Papers/pdfs/59f790.pdf

Michał Włodarczyk

Call for Nominations - HALG 2019

Call for Nominations

 4th Highlights of Algorithms conference (HALG 2019)

Copenhagen, June 14-16, 2019

http://highlightsofalgorithms.org/

The HALG 2019 conference seeks high-quality nominations for invited
talks that will highlight recent advances in algorithmic research.
Similarly to previous years, there are two categories of invited
talks:

A. survey (60 minutes): a survey of an algorithmic topic that has seen
 exciting developments in last couple of years.

B. paper (30 minutes): a significant algorithmic result appearing in a
paper in 2018 or later.

 To nominate, please email  halg2019.nominations@gmail.com  the
following information:

1. Basic details: speaker name + topic (for survey talk) or paper’s
title, authors, conference/arxiv + preferable speaker (for paper
talk).

2. Brief justification: Focus on the benefits to the audience, e.g.,
quality of results, importance/relevance of topic, clarity of talk,
speaker’s presentation skills.

All nominations will be reviewed by the Program Committee (PC) to
select speakers that will be invited to the conference.

Nominations deadline: December 9, 2018 (for full consideration).

Please keep in mind that the conference does not provide financial
support for the speakers.