Computational Complexity Blog

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Computational Complexity is a fun and popular computer science blog written by computational theorists Lance Fortnow and Bill Gasarch.

Computational Complexity Blog

2d ago

Recently
1) Avi Wigderson won the Turing Award (See blog posts by Fortnow-here, Scott-here, Lipton-Regan here, and the ACM announcement here). The last time I could find when Fortnow-Gasarch, Scott, Lipton-Regan all blogged on the same topic was when Goldwasser-Micali won the Turing Award- see the blog entries (here, here,here). We rarely coordinate. For that matter, even Fortnow and Gasarch rarely coordinate.
2) My joint book review of G.H. Hardy's A Mathematician's Apology (1940) and L.N. Trefethen's An Applied Mathematician's Apology appeared in SIGACT News.
The ..read more

Computational Complexity Blog

1w ago

The ACM announced that Avi Wigderson, a force in computational complexity and beyond, will receive the 2023 A. M. Turing Award (Quanta article). This is the first primarily complexity theorist to win the award since Andy Yao in 2000. Avi can add this to his Abel, Nevanlinna and Knuth prizes. Avi has served on the faculty at the Institute for Advanced Study since 1999 after many years at Hebrew University. He's hosted many postdocs and visiting faculty and students who've gone onto great careers of their own.
Avi is my first co-author to win the Turing award. Our paper was just one ..read more

Computational Complexity Blog

1w ago

My friend and colleague Rance Cleaveland passed away on March 27, 2024 at the age of 62. He was a professor at The University of Maryland at College Park in the Computer Science Department. He worked in Software Engineering. He did program verification and model checking. He had his own company, so he did both theoretical and practical work.
He joined UMCP in 2005. I had known him and some of his work before then so we got together for lunch about once a month to talk about the department(he was new to the dept. so I filled him in on things) and about computer science.He would pr ..read more

Computational Complexity Blog

2w ago

In a prior post I asked the following question:
find x,y,z positive natural numbers such that the following is true:
$$ \frac{x}{y+z} + \frac{y}{x+z} + \frac{z}{x+y} = 4. $$
I first saw the question in a more fun way:
I did not put the answer in the post (should I have? That was the meta question.)
The question has an infinite number of (x,y,z) that work, so I'll just give the least one:
x= 154476802108746166441951315019919837485664325669565431700026634898253202035277999
y = 36875131794129999827197811565225474825492979968971970996283137471637224634055579
z = 43736126779286972578 ..read more

Computational Complexity Blog

2w ago

1) Question: find x,y,z natural numbers such that the following is true:
$$ \frac{x}{y+z} + \frac{y}{x+z} + \frac{z}{x+y} = 4. $$
I was first presented the problem a more fun way:
(NOTE- a commenter pointed out that ``Natural Numbers'' and `Positive Whole Values' are different since some people (and I AM one of them) include 0 as a natural. SO- to clarify, I want x and y and z to be naturals that are \(\ge 1\). )
2) Meta Question: When a blogger poses a question like that should they also post the answer? Have a pointer to the answer? Not have an answer? Pros and Cons:
a) If you do no ..read more

Computational Complexity Blog

3w ago

Tech companies are performing exceptionally well, driving the S&P 500 to new heights with their soaring stock prices. However, the tech sector, apart from AI, expects a job decline to persist throughout the year, accompanied by a tougher hiring process. The situation becomes even more challenging for foreign students requiring sponsorship to secure a job after college, or older tech workers without the latest skills.
Despite these challenges, tech jobs remain more abundant than in most other fields, although the era of immediate employment with nearly six-figure salaries straight out of co ..read more

Computational Complexity Blog

3w ago

I am looking at LOTS of transcript of students who applied for my program REU-CAAR so I sometimes come across grades that I don't understand. The transcript does not have a guide to them, and I have been unable to find the meaning on line.
Normal grades of A,B,C,D,F possibly with + or - I DO understand, as do you, though standards differ from school to school.
UMCP also has
P for Pass in a course the student chose to take Pass-Fail
W for withdrawing from a course
WW which will be on all courses in a semester- so the student dropped out that semester
XF means failed ..read more

Computational Complexity Blog

1M ago

In the recent academy award winning movie Oppenheimer, Niels Bohr tests a young Oppenheimer.
Bohr: Algebra's like sheet music, the important thing isn't can you read music, it's can you hear it. Can you hear the music, Robert?
Oppenheimer: Yes, I can.
I can't hear the algebra but I feel the machine.
A Turing machine has a formal mathematical definition but that's not how I think of it. When I write code, or prove a theorem involving computation, I feel the machine processing step by step. I don't really visualize or hear the machine, but it sings to me, I feel it humming along, u ..read more

Computational Complexity Blog

1M ago

(Harry Lewis helped me with this post.)
March 15 was UMCP Computer Science Grad Student Visit Day. I suspect many of my readers are at schools that had their Grad Student Visit Day recently, or will have it soon.
In 1980 I got into Harvard Grad School in Applied Sciences. I went there in the Spring to talk to some people and take a look at the campus. I paid my own way- it did not dawn on me to ask them to reimburse me and I doubt they had the mechanism to do so.
I know a student who got into two grad schools in 1992 and contacted them about a visit. Both set up the visit and ..read more

Computational Complexity Blog

1M ago

La Scala in Milan
Google translate generally impresses but consider this translation from a short Italian news article. I boldfaced a few items.
Not scheduled at the premiere of Mozart's Die Entführung aus dem Serail (The Abduction from the Seraglio) which debuted this evening at La Scala.
During the second act, in fact, someone dropped a mobile phone from the stage and hit a spectator in the front row on the cheek.
'I'll report you,' the man who was hit shouted. And then at halftime he explained to the ushers that he would keep the smartphone until the owner arrived to repo ..read more