Why Doesn’t ACM Have a SIG for Theoretical Computer Science? – Guest post by Moshe Vardi

[Boaz’s note – this is another in the series of personal posts on STOC/FOCS reform, this time from Moshe Vardi, a renowned theoretical computer scientist who is also the editor in chief of the communications of the ACM. See also the discussion that’s still going on in the comment section of Omer Reingold’s post, as well all discussions under this tag.]

Why Doesn’t ACM Have a SIG for Theoretical Computer Science?

Moshe Vardi

Wikipedia defines Theoretical Computer Science (TCS) as as the “division or

subset of general computer science and mathematics that focuses on more

abstract or mathematical aspects of computing.” This description of TCS

seems to be rather straightforward, and it is not clear why there should be

geographical variations in its interpretation. Yet in 1992, when Yuri

Gurevich had the opportunity to spend a few months visiting a number of

European centers of research center, he wrote in his report, titled “Logic

Activities in Europe” that “It is amazing, however, how different computer

science is, especially theoretical computer science, in Europe and the US.”

(Gurevich was preceded by E.W. Dijkstra, who wrote an EWD Note 611 “On the

fact that the Atlantic Ocean has two sides.”)

This different between TCS in the US (more generally, North America) and

Europe is often described by insiders as “Volume A” vs “Volume B”, referring

to the Handbook of Theoretical Computer Science, published in 1990, with

Jan van Leeuwen as editor. The Handbook consisted of two volumes: Volume A,

focusing on algorithms and complexity, and Volume B, focusing on formal

models and semantics. In other words, Vol. A is the theory of algorithms,

while Volume B is the theory of software. North American TCS tends to be

quite heavily Volume A, while European TCS tends to encompass both

Volume A and Volume B. Gurevich’s report was focused on on activities of

the Volume-B type, which is sometimes referred to as “Eurotheory”.

Gurevich expressed his astonishment to discover the stark different

between TCS across the two sides of the Atlantic, writing that

“The modern world is quickly growing into a global village.”

And yet the TCS gap between the US and Europe is quite sharp. To see it,

one only has to compare the programs of the North American premier TCS

conferences–IEEE Symposium on Foundations of Computer Science (FOCS)

and ACM Symposium on Theory of Computing (STOC)–with that of Europe’s

premier TCS conference, Automata, Languages, and Programming (ICALP).

In spite of its somewhat anachronistic name, ICALP today has three tracks

with quite a broad coverage.

How did such a sharp division arose between TCS in North America and Europe?

This division did not exist prior to the 1980s. In fact, the tables of

content of the proceedings of FOCS and STOC from the 1970s reveal an

surprisingly (from today’s perspective) high level of Volume-B content. In

the 1980s, the level of TCS activities in North America grew beyond the

capacity of two annual single-track three-day conferences, which led to the

launching of what was known then as “satellite conferences”. Having shed

“satellite” topics, allowed FOCS and STOC to specialize, developing a

narrower focus on TCS. But the narrow focus of STOC and FOCS, the two

premier North American conferences, in turn has influenced what is

considered TCS in North America.

It is astonishing therefore to realize that the turn “Eurotheory” is

used somewhat derogatorily, implying a narrow and esoteric focus for

European TCS. From my perch as Editor-in-Chief for Communications, today’s

spectrum of TCS is vastly broader than what is revealed in the programs of

FOCS and STOC. The issue is no longer Volume A vs Volume B or Northern

America vs Europe (or other emerging centers of TCS around the world),

but rather the broadening gap between the narrow focus of FOCS and STOC

and the broadening scope of TCS. It is symptomatic indeed that unlike

the European Association for Theoretical Computer Science, ACM has no

Special Interest Group (SIG) for TCS. ACM does have SIGACT, a Special

Interest Group for Algorithms and Complexity Theory, but its narrow focus

is already revealed in its name [Paul Beame comments below that SIGACT stands for “Algorithms and Computation Theory” -B.].

This discussion is not of sociological interest only. The North

American TCS community has been discussing over the past few years

possible changes to the current way of running its two conferences,

considering folding FOCS and STOC into a single annual conference of

longer duration. A May 2015 blog entry by Boaz Barak is titled “Turning

STOC 2017 into a ‘Theory Festival'”. The proposal is focused on changing

the conference from the standard recitation of fast-paced research talks,

to a richer scientific event, with invited talks, workshops and tutorials,

social activities, poster and rump session, and the like.

I like very much the proposed directions for FOCS/STOC, but I’d also like to

see the North American TCS community show a deeper level of reflectiveness

on the narrowing of their research agenda, starting with the question posed

in the title of this editorial: Why doesn’t ACM have a SIG for Theoretical

Computer Science?