acm-header
Sign In

Communications of the ACM

Blogroll


bg-corner

From Computational Complexity

When does n divide a_n? The answer, though you already know it. The Point, though its not as strong as I wanted. Oh well.

In my last post When does n divide a_n? I gave a sequence: a(1)=0 a(2)=2 a(3)=3 for all n ≥ 4 a(n) = a(n-2) + a(n-3) and I noted that for 2 ≤ n ≤ 23 it looked...

From Computational Complexity

When does n divide a_n in this sequence?

Consider the following sequence: a(1)=0 a(2)=2 a(3)=3 for all n ≥ 4  a(n) = a(n-2)+a(n-3) Here is a table of a(n) for 2 ≤ n ≤ 23 n       2     3     4    ...

From Computational Complexity

What do Evolution, Same Sex Marriage, and Abstract Set Theory have in Common?

(This post is based on articles from 2012 so it may no longer be true. Also- to be fair- I tried finding stuff on the web BY the people who object to our children...

From Computational Complexity

New Ramsey Result that will be hard to verify but Ronald Graham things its right which is good enough for me.

If you finitely color the natural numbers there will be a monochromatic solution to x+2y+3z - 5w = 0 There is a finite coloring of the natural numbers such that...

From Computational Complexity

My third post on Gathering for Gardners

(Workshop for women in computational topology in August: see here. For a post about these kinds of workshops see here.) (I have already posted twice on stuffhere...

From Computational Complexity

Does this leak information?

Here are four fictional stories though inspired by real world events or TV shows (I forget which is which). My question is, was a confidence broken or was some...

From Computational Complexity

Math lessons from the Donald Trump Nomination (non-political)

There may be articles titled Donald Trump and the Failure of Democracy. This is NOT one of them. This is about some math questions. I drew upon many sources but...

From Computational Complexity

Some more bits from the Gathering for Gardner

I posted about the Gathering for Gardner conference and about some of the talks I saw here. Today I continue with a few more talks. Playing Penney's game with...

From Computational Complexity

Some short bits from the Gathering for Gardner Conference

I attended G4G12 (Gathering for Gardner) a conference that meets every 2 years (though the gap between the first and second was three years) to celebrate the work...

From Computational Complexity

Its hard to tell if a problem is hard. Is this one hard?

Here is a problem I heard about at the Gathering for Gardner. Is it hard? easy? boring? interesting? I don't know. Let N={1,2,3,...} PROBLEM: parameters are s...

From Computational Complexity

What Rock Band Name would you choose?

I looked up my colleague Dave Mount on Wikipedia and found  that he was a drummer for the glam rock band Mud. He informed me that (a) on Wikipedia he is David and...

From Computational Complexity

Are Perfect Numbers Bigger than Six initial sums of odd cubes (answered)

(NONE of this is my work. In fact some of it is on Wikipedia.) In my last blog I noticed that 28 = 13  + 33 496= 13 + 33 + 53 + 73 noting that 28 and 496 are...

From Computational Complexity

Are perfect numbers bigger than 6 initial sums of odd cubes?

I pose two questions today (Monday April 4). I will post the answers tomorrow (Tuesday April 5). Feel free to comment about the answers. If you don't want clues...

From Computational Complexity

Hillary Putnam passed away on March 13

Hillary Putnam passed away on March 13, 2016. Some of the obits say he  was a philosopher, mathematician, logician, and computer scientist. He is probably best...

From Computational Complexity

On Phillip Rogaway's The Moral Character of Cryptographic Work.

Some people have emailed me asking me to blog about the paper The Moral Character of Cryptographic Work by Phillip Rogaway  I urge you to read it, even if you disagree...

From Computational Complexity

When do we care about the constants?

I've been reading two books recently: Asymptopia by Joel Spencer (He turns 70 soon!  Workshop for it!. My nephew things that celebrating your bday with a workshop...

From Computational Complexity

It works in practice, but does it work in theory (Pollard's Factorization algorithm)

Throughout this post I ignore  polylog factors. It is trivial to factor N in time N1/2.  Pollard's rho-algorithm (see my write up here or Wikipedia Entry) for...

From Computational Complexity

What is a `previous publication'?

 Here are the guidelines about submission to STOC 2015 with regard to submitting a prior published paper. I assume that most of the Theory Conferences have a similar...

From Computational Complexity

∑{p≤ n} 1/p = ln(ln(n)) + o(1). read it here because....

(Last April fools day I  posted four links to stories that seemed absurd and asked which one was false. They all were true. I recently came across five  stories...

From Computational Complexity

Test of Time Award- a good idea but...

The ESA Conference (European Symposium on Algorithms) has a test-of-time award which recognizes outstanding papers in algorithms research that were published in...
Sign In for Full Access
» Forgot Password? » Create an ACM Web Account