|

This work is licensed under a
Creative Commons License.
|
Monday, October 31, 2005
Making Yourself Known
Posted by Lance
An assistant professor asks
How do I get on program committees and editorial boards?
PC chairs and editors-in-chief usually have several excellent
candidates to choose from so you really have to make yourself stand
above the crowd. How do you do this?
Prove. Easy said than done, but no better way to make yourself
known than by proving great theorems. Quality counts more than
quantity. Be sure to make your results public, by submitting them to
sites like ECCC as
well as putting them on your own homepage.
Talk. When you give a talk, take the time to prepare,
sell your work, make the talk understandable and
audience-appropriate. Someone told me recently they treated every talk
like a job talk. Not bad advice.
Meet. Go to workshops and
conferences not for the talks but to meet people. Don't just hang
out with people
from your own university. Skip some sessions, hang out in the
hallways and talk to whomever is around. Reconnect with your old
colleagues from graduate school and make an effort to meet new
people. Have lunch and dinner with people you don't know.
Write. Write up your research well so people enjoy rather than
suffer when reading your papers. Put some effort into your
introductions and really sell the importance of your work.
In addition
write a survey paper, write a book, write a
weblog. Get others to view you as an expert in the field.
Organize. Organize a workshop, do local arrangements for a
conference or other service to the community. I don't recommend this
route for assistant professors as it takes considerable time and won't
help your tenure case much.
Wait. Be patient. Your time will come.
1:27 PM
#

Sunday, October 30, 2005
List Decoding Beyond Expectations
Posted by Lance
The recent FOCS conference had two best paper award winners, the
Khot-Vishnoi paper I had
mentioned in my post
on unique games and Correcting
Errors Beyond the Guruswami-Sudan Radius in Polynomial Time by
Parvaresh and Vardy.
List decoding considers codes where we have too many errors in the
code to uniquely decode a
string. These algorithms
creates a short list of all of the
possible decodings.
Last year I had discussed
list decoding in my Favorite Theorems series and said
Guruswami and Sudan
give a polynomial-time algorithm that handles what is believed to
be the best possible amount of error.
Guruswami and Sudan's algorithm works for the standard Reed-Solomon
codes and is likely the best possible for that code. Parvaresh and
Vardy develop a new but related encoding to get an
improvement on the rate of the code, the ratio of the original message
length to the code length. Guruswami and Sudan show how to list
decode a 1-ε fraction of errors using Reed Solomon codes with a rate of
O(ε2) while Parvaresh and Vardy achieve the same errors with
their code with rate O(ε/log(1/ε)).
6:51 AM
#

Friday, October 28, 2005
Algorithms for a Ten-Year Old
Posted by Lance
Yesterday my fifth-grade daughter, doing her math homework, asked
Is there a faster way to find greatest common factors other than with
factor trees?
I live for these days. After I impressed her with Euclid's algorithm
she asked
Is there a faster way to factor than with factor trees?
I thought for a while and then just answered "No."
5:55 AM
#

Thursday, October 27, 2005
Joy on the South Side of Chicago
Posted by Lance
7:50 AM
#

Wednesday, October 26, 2005
Selling Theory
Posted by Lance
Thanks to Rocco for bringing us the news from FOCS, particularly a
comprehensive summary
of the business meeting. I am glad to have watched my White Sox in the
World Series live and read a recap of the business meeting than the
other way around.
A number of bloggers including Scott,
Suresh,
Sariel
and physicist David
Bacon have weighed in on the big panel discussion on
how to generate interest in theoretical computer science. There was a
big push for our community to publish in Science and
Nature. I have seen more than a couple rather mediocre CS
papers in Science. We need more than to just send our papers to
these journals, we need members of our community on the editorial
board.
The most interesting comments came from science writer Sara Robinson.
There is a perception among science editors that TCS is not what
people want to read about: they want stories about health, things that
cost a lot of taxpayer dollars, etc.
The New York Times, which Sara Robinson has written for in the past,
used to give good coverage to research in theoretical computer
science. But their Tuesday section Science
Times has moved over the last couple of years from a general covering of
science to a focus on medicine, environment and astronomy. Not just
computer science but physics and chemistry get far less coverage than
they once did.
What scares me most is what I see from incoming undergraduates. Far
more high school students use computers now than say ten years ago but
far fewer of them know how to program. Computer science is a victim of
its own success, by making computers powerful, easy to use and
well-connected, we have turned computers into a commodity like cars
with the mystique of computation and complexity lost on the users.
4:26 PM
#

Page Six
Posted by Rocco Servedio
Final guest post from FOCS attendee Rocco Servedio.
Well, another FOCS has come and gone. In 50 years -- 100, tops -- we will know which papers from the conference stood the test of time. But meanwhile on to more pressing matters. Last week Lance promised that I would provide "all the gossip from the conference;" I'd hate to disappoint, so here goes. All names have been changed to protect the guilty, and pronouns should not be used to infer gender. Presenting...
"THE THEORY TATTLER"
- POTTED PROFESSOR: WHICH thirsty theorist drank so much beer at the business meeting that his PhD students had to help him back to his room? The greedy guzzler was next spotted Monday afternoon nursing a mug of black coffee in the back row and wincing at microphone feedback.
- DINNER DILEMMA: WHICH graph theory guru created an scheduling snafu when he separately told two rival gangs of theorists that he'd "meet you in the lobby in 15 minutes?" Let's hope his administrative assistant at Famous University manages things better when he's on his home turf.
- ENOUGH ALREADY! WHICH logorrheic logician went so far over time that he "practically had to be dragged off the podium?" Our sources say the session chair was scant seconds from pulling the projector plug when the babbling bore finally zipped it.
- HEARTBREAKER: WHICH complexity theorist Casanova has a love life that's more complicated than the proof of the Parallel Repetition Theorem? It seems there's no lower bound on this cheating cad's bad behavior.
Sadly, as you've probably guessed, none of these things actually took place (or if they did I didn't know about it; if so that's even sadder). In all seriousness, thanks to Lance for letting me post these last few days; it was fun, especially the chance to branch out into fiction-writing at the end.
1:11 AM
#

Tuesday, October 25, 2005
Knuth Prize
Posted by Rocco Servedio
The 2005 Knuth Prize was awarded to Mihalis Yannakakis of Columbia University. Mihalis's Knuth prize lecture was on "Probability and Recursion."
12:29 AM
#

Monday, October 24, 2005
FOCS Business Meeting
Posted by Rocco Servedio
Notes from the FOCS 2005 business meeting, reported by
Rocco Servedio.
Yuengling, Sam Adams, Aspen Edge (low-carb).
Local arrangements:
There were 144 non-student registrants and 141 students for a total of
285 registered attendees.
Thanks to Avrim Blum and Anupam Gupta for a job well done on local
arrangements.
An interesting fact: doing local arrangements ourselves saves
about $100/person on registration fees.
PC report:
There were 268 submissions. 7 papers were retracted (an all-time high?); two
of these were because of bugs found by the PC and five were initiated by the
authors. Authors are encouraged to submit correct papers.
There are 62 papers in the proceedings; 3 pairs of papers were merged
(these papers got extra space in the proceedings).
Distribution of authors (multiple papers means you get counted multiple times):
121 from U.S.A.,
23 from Israel. 6 from Canada. 3 from Denmark, Italy,
2 from Germany, India, Czech, Hungary,
1 from Poland, Netherlands, Japan.
Average # of authors per paper is 2.64 (or 2.48 depending on how
you count merged papers). There were 7 single-author papers.
The two papers that were selected for Best Paper awards are
"The Unique Games Conjecture, Integrality
Gap for Cut Problems and Embeddability of Negative Type Metrics
into \ell_1" by Subhash Khot and Nisheeth Vishnoi, and
"Correcting Errors Beyond the Guruswami-Sudan Radius in Polynomial Time" by
Farzad Parvaresh and Alexander Vardy.
Two papers shared the Machtey Award for the best paper authored
solely by students. These were
"On the Complexity of Real Functions" by Mark Braverman
and "On the Complexity of Two-Player Win-Lose Games"
by Tim Abbott, Daniel Kane, and Paul Valiant.
As all readers of this weblog know, the next CCC (Computational
Complexity Conference) will be held in Prague from July 16-20, 2006.
The submission deadline is December 4.
LICS 2006 will held in Seattle in August 2006 as part of the Federated Logic
Conference.
FOCS 2006 will be held in Berkeley; Sanjeev Arora will be PC chair.
Following an entertaining "Star Wars" themed bid, it was decided that
FOCS 2007 will be held in Providence.
STOC 2006 will be held May 20-23, 2006 in Seattle.
The submission deadline is November 3 (so stop reading this weblog and
get back to work).
SPAA 2006 will be held July 30-August 2, 2006 in Cambridge, MA.
There was a panel discussion on "Exciting the public about (theoretical)
computer science."
The panelists were Bernard Chazelle, Dick Lipton,
Ivars Peterson (writes about math and computer science for Science News),
Sara Robinson (freelance writer in math and CS), Steven Rudich, and Eva Tardos;
Avrim Blum moderated the discussion. A few fragmentary
snapshots from the discussion:
Chazelle: Computing has never been more important, and never been more
misunderstood. We are not doing as good a job of getting our work into
the public eye as other fields such as physics. If the broader scientific
community comes to use algorithms as a conceptual framework for the problems
they are dealing with, we will have done well.
Lipton: We have lots
of really profound and interesting intellectual challenges; one way to excite the public
is to talk to them about these fundamental questions.
Rudich: How do we take what are doing and translate it into problems that
people can relate to and care about? We have a million forms
of encoding and should be able to do this;
everyone can relate to the problem of trying to pack items into a
suitcase of limited size.
Tardos:
Whatever you do, it is probably possible to explain it to the public.
There is an awful lot of stuff we do that is really not that hard to explain.
A straw poll of the audience showed that very few people in our community
have ever published in Science or Nature; it would be good
if this could change.
Peterson:
Publicity takes effort.
The American Chemistry Council is spending twenty million dollars
on advertising to sell the importance of research in chemistry.
Astronomy often gets the front page of The New York Times; this is
because of carefully orchestrated arrangements behind the scenes.
The ACM, SIAM, IEEE do no publicity that I (Peterson) am aware of as
a journalist.
To get into the media: publish in Science and Nature. Lay language summaries
and images are provided to the media a week in advance of each issue.
There is always a Nature story in the newspaper
on Thursday and a Science story on Friday.
For newspaper coverage,
one writer or a very small group can make a difference.
Robinson: Even all the approaches suggested above will have only a limited effect.
Two reasons for this: (1) Theoretical computer science is hard to understand
for the lay public and for reporters (and, as one audience
member shouted out, for us). It is easier to write about global warming
or why the coyotes are multiplying. (2) There is a perception among science
editors that TCS is not what people want to read about: they want stories
about health, things that cost a lot of taxpayer dollars, etc.
Perhaps we should explore new models such as a dedicated math/science news
agency?
(anonymous science writer audience member): "People like dinosaurs, asteroids,
and things coming out of the ground...very little of what you guys have is concrete."
Finally, Dick Karp gave a report on behalf of the SIGACT committee on funding
for theoretical computer science.
The main goal of the committee is to improve stature and support of TCS
within NSF.
Based on a sample of 90 TCS investigators receiving
funding between 2000 and 2004, 23% of funding came from TCS Foundations of
Theoretical Computer Science and 55% came from ITR grants (now terminating).
The average number of grants/year received per investigator was 2.4, and the
median grant size per investigator per year was $70K.
The 2005 TCS budget is about $6M.
Some concrete items on the agenda for the future are to make a well-documented case that
TCS is underfunded and to move TCS up a level in the CCF hierarchy.
12:09 AM
#

Sunday, October 23, 2005
First day of FOCS
Posted by Rocco Servedio
A guest post from FOCS attendee Rocco Servedio.
Thanks to Lance for giving me this opportunity to fill in. I'm in
Pittsburgh for FOCS, which started today and runs through Tuesday.
Unfortunately because of travel constraints I couldn't make it to the
Frieze Fest or FOCS tutorials that took place yesterday.
Pittsburgh is a city which sometimes gets a bad rap, but I've always
enjoyed coming here. Besides the obvious -- at least for this blog's
readers -- attraction of CMU, there are lots of neat things that you can't
find anywhere else. I personally like the National Aviary, and the Carnegie museums
are fun too. At the Warhol museum you
can watch movies that make even the driest FOCS talk seem like a Jerry
Bruckheimer production.
No time for museums today, though; the FOCS schedule is full of
cool-looking talks, and tonight there is the business meeting and a panel
discussion on "Exciting the public about (theoretical) Computer Science."
I'll give a report on the business meeting and panel discussion later.
10:14 AM
#

Thursday, October 20, 2005
Math in Complexity
Posted by Lance
Another guest post by Bill Gasarch
Combinatorics is a branch of Computer Science
First episode, Second Season of NUMB3RS
I could have a post on how stupid this statement is,
I'd rather ask the following better question:
How much do we use Combinatorics in Complexity Theory?
Do we use anything else?
Towards this end I looked through the COMPLEXITY 2005 proceedings
and assigned to
each paper what sort of math I thought they
used. I'm sure some can be argued. But here are the results:
-
Probability: 8
-
Combinatorics: 6
-
Linear Algebra: 6
-
Abstract Algebra: 4
-
Number Theory: 2
-
Diagonalization and Simulation: 2
-
Calculus: 1
-
Dynamic Programming: 1
-
Philosophy: 1
OBSERVATIONS:
-
Very little continuous math. Even the Linear Algebra
is usually over a finite field.
-
Very little Diagonalization/Simulation. This is part of the general
trend away from methods of logic. I suspect there was a lot
more of those at the first STRUCTURES back in 1986.
-
More abstract algebra than I would have thought, but I don't know
if this is unusual or not.
9:04 PM
#

Wednesday, October 19, 2005
Football Schools
Posted by Lance
I am spending most of this week at the University of Nebraska for a talk
and a workshop. What does
Nebraska have to do with Notre Dame, where I visited last month? Both
are traditional football powerhouses, a place where the sport
dominates the school and more Americans know these universities for
their teams than their academics. I've heard most universities
actually lose money on their football programs (though Notre Dame is
an noted exception). Still schools use football to attract students, raise
school spirit and bring back alumni and their money. In many states
the highest paid public employee is the football coach. Notre Dame
attracted a star professor by promising him season tickets
"between the 45s" and Nebraska smartly has an admissions
office inside the stadium.
Many foreigners find the level of US college athletics surprising but
having grown up in this country I was shocked to find out European
universities, for the most part, do not play each other in any
sport, not even soccer. Where's the fun in that?
My next university trip will be to the University of Rochester, not a
football powerhouse and in the same Division III wannabe-ivy league as the
University of Chicago. Chicago used to be a football powerhouse, part
of the Big Ten and had the first Heisman trophy winner, Jay
Berwanger, in 1935. But then the new president Robert Maynard Hutchins
who has been claimed to say "Whenever I feel like exercising, I
lie down until that feeling goes away," eliminated the athletic
programs and focused the university on academics. Only in the past few
decades have they even had Division III teams.
With all this traveling, I won't be going to FOCS. But don't worry, I have
lined up a special guest blogger to bring us all the gossip from the
conference.
6:14 PM
#

Tuesday, October 18, 2005
Finding Nash has Same Complexity as Finding Fixed Points
Posted by Lance
In a new paper,
Daskalakis, Goldberg and Papadimitriou show that finding Nash
Equilibrium in matrix games with four or more players is complete for
the search class PPAD. PPAD is best described by the problem: Given an
exponential-size direced graph with every node having in-degre and
out-degree at most one described by a polynomial-time computable
function f(v) that outputs the predecessor and successor of v, and a
vertex s with a successor but no predecessors, find a t≠s that either has no
successors or predecessors. The underlying combinatorial statement
that such a t exists is used to prove Sperner's
Lemma which can be used to prove the Brouwer
fixed point theorem which in turn can be used to prove the
existence of Nash Equilibrium.
The authors leave open the complexity of finding Nash Equilibrium for
two and three players. They conjecture that for three players the
problem remains complete for PPAD but two player Nash Equilibriums can
be found in polynomial time.
2:18 PM
#

Monday, October 17, 2005
True Impact
Posted by Lance
How do you measure your impact as a computer scientist? You can try measures
like the Citeseer
rank or the h-index, but
the only scientifically
valid test would compare the world today with the world where you
were never born.
We can never actually run such a test but we can try the thought
experiment. Even if you are one of the "greats," most of
your theorems, even the best and most surprising, would have been
eventually proved a few months or a few years later. Other
theorems would never have
been proved because no one, other than the non-existent you, would
have cared. Other than
speeding up science a little bit, you cannot get a long-term
individual impact on the field solely by proving theorems.
But proving those theorems builds your reputation and with that
reputation you can shape the direction of the field. With this
reputation you can, for better or for worse, help shape the direction
of the field and set the research agenda for a generation of young
graduate students. You also have lasting influence through your
graduate students and the undergrads you convince to study computer
science.
We can run this thought experiment the other way. Suppose many years
ago a sperm darted right instead of left and fertilized an egg that
hatched a true genius in our field. How much difference could that one
person have made on our research and our lives?
10:41 PM
#

Sunday, October 16, 2005
Blogging and Academics
Posted by Lance
The University of Chicago denying tenure to an assistant professor is
rarely a breaking news story. Yet political scientist Daniel Drezner's
case received considerable press including a Chicago Tribune story.
Why? Because he had a popular blog.
I doubt the content of the weblog or its existence or popularity
played negatively towards his tenure case. Perhaps some feel his time
would have been better spent on "real academics" but most
likely they considered his more traditional academic writings and,
frankly, it's very difficult to get tenure at the U of C, particularly
in the social sciences.
Will Drezner's weblog help him in his future job hunt? Ivan Tribble
argued
that weblogs can hurt a candidate for an academic position.
The content of the blog may be less worrisome than the fact of the
blog itself. Several committee members expressed concern that a
blogger who joined our staff might air departmental dirty laundry
(real or imagined) on the cyber clothesline for the world to see. Past
good behavior is no guarantee against future lapses of professional
decorum.
I disagree with Tribble. Most non-anonymous academic webloggers know
better than to discuss departmental politics in their blogs and
departmental hiring committees should or will realize they have
nothing to fear. A popular weblog raises one visibility in and out of
their field—far more people read this weblog then download my
research papers, for example. A weblog like Daniel Drezner's (much
more read than this one) gives him an edge over his peers, a
popularity that will open some doors that others will have to fight
harder for.
7:11 AM
#

Thursday, October 13, 2005
Fonts
Posted by Lance
Fonts are the last thing I want to worry about when I write a research
paper. Unfortunately fonts have often become the last thing I need to worry
about when I write a research paper.
In the olden days (circa 1990), we all wrote our LaTeX
papers using the Computer Modern font. When we sent a paper to a
proceedings we printed up a clean copy and sent it via Federal Express.
Now we have choices of fonts. Fonts are a surprisingly complicated
process. A good font is a work of art and a
scalable font is actually a computer program for each letter. If you
intellectual property issues for digital music is complicated, IP for
typefaces is nearly impossible to implement well.
When some societies like the IEEE first started taking electronic
uploads for their proceedings we would get the occasional disastrous
effects because the IEEE fonts didn't match the fonts people used to
create a paper. For example the "<" would appear as
a "⇒" making some of the papers unreadable. Most of
these organizations have become more aware of this issue but now
require us to jump through some hoops (use the right fonts and style
files and putting the paper in the appropriate format using the right
program to do so). Makes me wish for the old days when I could send a
paper and they would scan it, which the IEEE will still do but charge
extra for.
Sometimes you'll see "¿From" in older
papers. This is not a font problem but a property of sending text
files through email would add a ">" to a line beginning
with "From" which would come out "¿From"
after LaTeX processed the file. You see it less now as files get sent
via attachments instead of directly in the mail body.
Distractions from worry about something as minor as fonts really keeps
us away from focusing on research and other important
activities. Remember, no one was ever denied tenure for bad font
selection.
10:05 PM
#

Wednesday, October 12, 2005
Early or Late
Posted by Lance
As you can see from the timestamp of this post, I came into work quite
early this morning. I had to drive and needed an early start (about 6 AM) to beat
Chicago traffic and get a good parking spot. When I arrived I saw
another professor in his office. I knew he wasn't the early type and
likely spent the night here. When I said "Hello," he replied
"Deadline."
Which one of us is keeping the crazier hours?
7:23 AM
#

Monday, October 10, 2005
Favorite Theorems: Logical Characterization of NP
Posted by Lance
September Edition
Usually we think of the class NP as either languages accepted in
polynomial-time by a nondeterministic Turing machine or languages with
polynomial-time verifiable witnesses. Ronald Fagin gives a
characterization of NP based on logic without references to Turing
machines or polynomial time.
Ronald Fagin, Generalized
first-order spectra and polynomial-time recognizable sets. Complexity
of Computation, ed. R. Karp, SIAM-AMS Proceedings 7, 1974, pp. 43-73.
In this paper Fagin shows that NP consists of exactly the languages
expressible with existential second-order formulas. For example
consider a graph G described by an edge relation E(i,j) and we can
define whether G is k-colorable by
∃C ∀i,j (1≤C(i)≤k ∧
(E(i,j)→C(i)≠C(j)))
With some more work you can use binary predicates. In general every
language in NP has an existential second-order characterization with
binary predicates and a universal first-order part.
Stockmeyer generalizes
Fagin's result to characterize the polynomial-time
hierarchy with second-order formulas.
Fagin's result started the area of descriptive
complexity that characterized many common complexity classes in
various logics and has connections to the complexity of database
queries. Neil Immerman's work in descriptive complexity led him to his
proof
that nondeterministic space is closed under complement. Robert
Szelecpsényi independently came up with a similar proof through
a different approach.
Papadimitriou and Yannakakis use Fagin's result to characterize
the class MAX-SNP of optimization problems. One of the first
corollaries of the PCP Theorem is to
show the MAX-SNP hard problems cannot be approximated within an
arbitrary constant unless P=NP. In fact the concept of
probabilistically checkable proof itself originally comes from a
second-order view of NP that originated from Fagin's paper.
Update 10/12: Fagin adds an addendum.
Thanks to Lance and Siva for the kind words about my theorem. Let me
clarify the story on the arity of the existentially quantified relations.
An existential second-order formula about, say, graphs, is a formula of the
form
∃ Q1 ... ∃ Qk S( E, Q1, ...,
Qk)
where E represents the edge relation, Q1, ..., Qk are
existentially quantified predicates of arbitrary arity, and S(E,
Q1, ..., Qk) is a first-order formula that involves
only E, Q1, ..., Qk. As an example, 3-colorability
of the graph can be expressed by an existential second-order formula
∃ Q1 ∃ Q2 ∃ Q3 S(E,
Q1, Q2, Q3),
where Q1, Q2, and Q3 are unary predicates
(that represent the 3 colors), and S(E, Q1, Q2,
Q3) is a first-order formula that says "Each point has exactly
one color, and no two points with the same color are connected by an
edge''.
In the case of graphs, my theorem says that if T is a class of graphs that
is closed under isomorphism (that is, whenever T contains a graph G, then
it contains every graph isomorphic to G) , then T is in NP if and only if T
is defined by an existential second-order formula. In the case of graphs,
it is an open problem as to whether we really need to allow existentially
quantified predicates of arbitrary arity. On the one hand, it is
conceivable that there are NP properties of graphs that require
existentially quantified predicates of arbitrarily large arity. On the
other hand, it is conceivable that we can capture every NP property of
graphs by allowing only a single existentially quantified binary predicate.
If we consider NP properties not just of graphs, but of arbitrary
structures (such as structures with, say, two ternary relations and five
7-ary relations), then the characterization of NP in my theorem continues
to hold, but in this case, it is known that existentially quantified binary
predicates do not suffice. In particular, Ajtai proved (in the same
amazingly rich 1983 paper [Σ11-formulae on
finite structures, Annals of Pure and Applied Logic 24, 1983, pp. 1-48]
where, among other things, he proved the Furst-Saxe-Sipser theorem
independently of Furst, Saxe and Sipser), that if we consider structures
consisting of a single m-ary relation, then the statement "The number of
m-tuples in the relation is even" cannot be captured in existential
second-order logic with any number of existentially quantified predicates
of arity less than m.
A gentle introduction to the work I've mentioned in this note and to some
other work in finite model theory appears in my survey paper
Finite
model theory-a personal perspective.
4:45 PM
#

Sunday, October 09, 2005
A New Packard Fellow
Posted by Lance
Piotr Indyk, himself a 2003 Packard Fellow, writes
On the recent blog topic of awards: you might be interested to know that Venkat
Guruswami just
received a Packard Fellowship.
Congrats to Venkat for recognition (and money) well deserved.
7:58 PM
#

Saturday, October 08, 2005
NP-Completeness Papers
Posted by Lance
A colleague is refereeing a paper in a non-computer science area that
shows a certain computational problem is NP-complete. The proof uses a
simple reduction from a standard NP-complete problem. Should such a
result be published? As long as people really care about the
computational problem, then yes, such results should be published.
The greatest gift of computational complexity to society is the
ability to use NP-completeness to show that a large variety of
problems are likely hard. The field has also developed many tools to
help easily show such problems are NP-complete. We shouldn't penalize
people for using these tools.
This is one of those cases where having a "simple proof"
hurts the paper. If the paper used PCP technology in the proof it
would without question be published. And if the paper relied on the unique
games conjecture (and thus a weaker result) the paper would likely
get accepted into STOC.
11:38 AM
#

Thursday, October 06, 2005
Unix Free Since 1999
Posted by Lance
My first computer was a TRS-80, my second an Apple IIe. In college I
mostly programmed in IBM 370 assembly code. But in graduate school
(first at Berkeley and then at MIT) I starting using Unix in its
various forms and its programs, first Vi
and Troff, then Emacs and LaTex and reading email via the command
line "mail."
My future wife had one of the early "IBM Compatible" PCs and
I liked some of the programs one could use, like Quicken, Prodigy (an
information dial-up service), good spreadsheets and word
processing. My home computer has always been a DOS/Windows machine
since.
Windows had good calendar and email programs long before they were
available for Unix so at one point I got a PC card for the Sun in my
office which ran Microsoft Windows in an Unix window. As I found
myself spending more and more time in that window, my next machine was
a Windows machine with an X-Windows program so I could connect to the
department's Unix machines to use Emacs and LaTex.
Soon very good Emacs and LaTex programs became available for Windows
and when I moved to NEC in 1999 I went Unix free and haven't looked
back. My biggest complaint about Unix was the user interface. To print
pages 3 to 5 of a latex document is easy in windows, for Unix I had to
do a man dvips since I could never keep straight which flags did
what. Once I spent hours trying to figure out what I did wrong in a
Make program (I had uses spaces instead of tabs). I'll never forget
the time I accidentally typed "rm temp *" instead of
"rm temp*".
Ever since people have kept telling me Linux interfaces and programs
have gotten much better, and they have, but never enough to get me to
switch back. Some Apple lovers have tried to get me to move to
Apples, but they just never had the software available that PCs
do. Windows emulators for Apples are popular but you don't see the
need for the other direction.
As more and more of the programs I use become web based, the actual
platform becomes less and less important. Still though as someone who
likes an easy user interface and wide availability of programs and
doesn't do much programming and scripting, Windows has worked well for
me.
5:55 PM
#

Wednesday, October 05, 2005
Tradition
Posted by Lance
A conversation with a graduate student today.
- Student: Why doesn't FOCS have a best paper award
this year?
- Me: They often don't announce the winners until the conference
begins.
- Student: Traditionally the best paper get
longer talks and there are none scheduled.
- Me: There's no such thing as tradition at STOC and FOCS. Rest
assured (though I have no prior knowledge) there will be a best paper
award given.
I've heard that by tradition FOCS has had single sessions and STOC has
had parallel sessions. Not long ago both had parallel sessions and
before that FOCS had the parallel sessions (the first time with a two
volume proceedings) and STOC had single sessions, and before that both
had single sessions. STOC/FOCS used to be Monday-Wednesday, now they
are Saturday-Tuesday and sometimes not. STOC/FOCS were always in North
American and then they weren't. FOCS once had the only best student
paper award and then had the only best student paper award named after
somebody. Now they both do. We've had invited speakers. We've not had
invited speakers. We've had tutorials. We've not had tutorials. One
day one of the conferences will have electronic proceedings and the
other won't and that will be tradition.
The decisions of how STOC and FOCS are run are up to the program
committee with constraints on schedule and the local arrangements
site. Two or three years of the same in a row becomes a
"tradition" and hard to change. But we shouldn't let these
"traditions" prevent us from running the best possible
conferences and nor should you count on them to continue as
is. Traditions keep us in the past, change pushes us to the future.
10:07 PM
#

Tuesday, October 04, 2005
DNA Testing for Sports
Posted by Lance
In the second biggest sports story in Chicago (after the White Sox
rout of
Boston), the Chicago Bulls basketball team
traded
Eddy Curry to the New York Knicks. The Bulls had wanted Curry
to take a DNA test to check for a certain heart condition and Curry
refused so finally they decided to trade him to the Knicks who will
not require the DNA test. I understand the Bulls' position but testing
DNA for diseases for employment opens up a big can of worms. Shades of
Gattaca?
On a completely different note, one-time guest blogger Scott Aaronson
has joined the
blogosphere himself. What took him so long?
9:04 PM
#

Monday, October 03, 2005
Euthanizing a Virtual Pet
Posted by Lance
We had a high pitch tone coming from somewhere in our family room but
we couldn't find the source. I shut down the power in case the sound
was coming from the stereo system or lights but the tone
remained. Finally we found the culprit, my daughter's
Tamagotchi buried under some books.
Pressing the buttons failed to quiet the device, so I attempted to
open the unit up to remove the battery. When that failed I finally
put the Tamagotchi in a plastic bag and hit it several times with a
hammer until it finally shut up.
Later I confessed the destruction of the virtual pet to my daughter
who seemed not to care in the least. The fad had ended.
But next on my daughters' wish list: Nintendogs.
1:07 PM
#

Sunday, October 02, 2005
Awards
Posted by Lance
The Nobel Prizes will be announced
this week and I predict that no one will win the Nobel Prize in
computer science for the 105th consecutive year. Computer Science's
highest honor, the Turing Award will be
announced in early 2006 (February 16 last year).
We also have some awards coming up for theorists. At every third
STOC/FOCS conference, the Knuth Prize is given for
outstanding sustained contributions to theoretical computer
science. We will find out the next winner at the upcoming FOCS Conference in a couple
of weeks.
Every four years the International Math Union awards the Nevanlinna
Prize for contributions in "mathematical aspects of information
sciences" to a scientist under forty. The previous
winners have all been computer science theorists and we have several
excellent candidates for the 2006 prize as well.
ACM SIGACT sponsors or co-sponsors several other awards such as the Gödel Prize given
to the best recent journal paper (where the definition of
"recent" keeps changing) and the Paris Kanellakis Theory and
Practice Award given to theorists whose work had practical applications.
9:26 AM
#

|