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Published By Association For Computing Machinery

0163-5700
Updated Tuesday, 18 January 2022

2021 ◽  
Vol 52 (4) ◽  
pp. 80-96
Author(s):  
Felix Hohne ◽  
Soren Schmitt ◽  
Rob van Stee

In this column, we will discuss some papers in online algorithms that appeared in 2021. As usual, we make no claim at complete coverage here, and have instead made a selection. If we have unaccountably missed your favorite paper and you would like to write about it or about any other topic in online algorithms, please don't hesitate to contact us!


2021 ◽  
Vol 52 (4) ◽  
pp. 74-75
Author(s):  
Dan Alistarh

Overview. In this column, we combine traditional content for the December edition, namely a perspective on the paper which received the 2021 Dijkstra Award, but we also depart of from tradition, by not having our traditional articles covering the PODC and/or DISC proceedings.


2021 ◽  
Vol 52 (4) ◽  
pp. 15-17
Author(s):  
S.V. Nagaraj

This book is about algorithms and their enormous influence on people in the current age. Algorithms are precise sets of rules to solve problems. They are ubiquitous and have a great effect on the lives of contemporary people, primarily due to technological advancement. A common example is searching for information using an Internet search engine such as Google. This book is not technical in nature and was first published in French as Le Temps des Algorithmes, by ´ Editions Le Pommier in 2020. The authors Serge Abiteboul and Gilles Dowek are computer scientists, with Institut National de Recherche en Informatique et en Automatique (INRIA), Rocquencourt and ´ Ecole Normale Sup´erieure, Paris respectively. They believe that algorithms have made life easier, nevertheless, they dread that algorithms may subjugate humans. This book is intended to serve as an eye-opener on the impact of algorithms on daily life.


2021 ◽  
Vol 52 (4) ◽  
pp. 18-30
Author(s):  
Dean Kelley

Welcome to the Technical Reports Column. If your institution publishes technical reports that you'd like to have included here, please contact me at the email address above.


2021 ◽  
Vol 52 (4) ◽  
pp. 55-55
Author(s):  
Lane A. Hemaspaandra
Keyword(s):  

This issue's complexity theory column is by Ben Lee Volk on algebraic natural proofs. My warmest thanks to Ben Lee for his terri c article.


2021 ◽  
Vol 52 (4) ◽  
pp. 6-10
Author(s):  
Frederic Green

The future prospects for anyone falling into a black hole are bleak. For one thing, there is no chance (according to our present state of knowledge) of ever getting out again. Worse, one is facing certain destruction when one meets the "singularity" (or its inconceivably dense physical manifestation, whatever that may be) inside. However, there is an "event horizon," the point of no return, separating the overly curious infalling astronaut from the doom he or she faces at the singularity. Suppose Alice the Astronaut wants to see what's behind the horizon (never mind the consequences). How much time would Alice have to look around and see what's happening, before reaching the end of her worldline? Conventional wisdom, until relatively recently, was that she would have some amount of time, perhaps hours. Passing the event horizon of a supermassive black hole would not seem like any kind of a milestone to the infalling individual; it is only an outside observer who would notice something out of the ordinary.


2021 ◽  
Vol 52 (4) ◽  
pp. 3-5
Author(s):  
Frederic Green

The first two reviews in this column draw from the "SpringerBriefs" series, dedicated to compact summaries of cutting-edge research in a variety of fields. The first is from SpringerBriefs in Physics, the second from SpringerBriefs in Applied Sciences and Technology. We close with a review about algorithms in the context of the modern world.


2021 ◽  
Vol 52 (4) ◽  
pp. 56-73
Author(s):  
Ben Volk

Algebraic Natural Proofs is a recent framework which formalizes the type of reasoning used for proving most lower bounds on algebraic computational models. This concept is similar to and inspired by the famous natural proofs notion of Razborov and Rudich [RR97] for boolean circuit lower bounds, but, unlike in the boolean case, it is an open problem whether this constitutes a barrier for proving super-polynomial lower bounds for strong models of algebraic computation. From an algebraic-geometric viewpoint, it is also related to basic questions in Geometric Complexity Theory (GCT), and from a meta-complexity theoretic viewpoint, it can be seen as an algebraic version of the MCSP problem. We survey the recent work around this concept which provides some evidence both for and against the existence of an algebraic natural proofs barrier, with an emphasis on the di erent viewpoints and the connections to other areas.


2021 ◽  
Vol 52 (4) ◽  
pp. 11-14
Author(s):  
Abdulai Gassama ◽  
Frederic Green

Computational geometry and topology are huge branches of mathematics. Focussing on concepts that lead to computation is one strategy to provide a concrete conceptual basis for ideas that hold in a more general context. Indeed, this short book gives an introduction to a surprisingly broad range of ideas that can serve as a good introduction to geometry and topology (even broadly conceived) for undergraduates.


2021 ◽  
Vol 52 (4) ◽  
pp. 31-54
Author(s):  
Andrei Romashchenko ◽  
Alexander Shen ◽  
Marius Zimand

This formula can be informally read as follows: the ith messagemi brings us log(1=pi) "bits of information" (whatever this means), and appears with frequency pi, so H is the expected amount of information provided by one random message (one sample of the random variable). Moreover, we can construct an optimal uniquely decodable code that requires about H (at most H + 1, to be exact) bits per message on average, and it encodes the ith message by approximately log(1=pi) bits, following the natural idea to use short codewords for frequent messages. This fits well the informal reading of the formula given above, and it is tempting to say that the ith message "contains log(1=pi) bits of information." Shannon himself succumbed to this temptation [46, p. 399] when he wrote about entropy estimates and considers Basic English and James Joyces's book "Finnegan's Wake" as two extreme examples of high and low redundancy in English texts. But, strictly speaking, one can speak only of entropies of random variables, not of their individual values, and "Finnegan's Wake" is not a random variable, just a specific string. Can we define the amount of information in individual objects?


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