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From Computational Complexity

Algorithms that never get coded up

(There was a passing ref to this topic in the comments to one of Scott's blogs, so I thought I would pick up the theme.) When I teach Formal Lang Theory I endCould...

From Computational Complexity

Luddite or not?

My first ever guest post for Lance was on Are you a luddite. I certainly am to some extent a luddite, but there are some things where it not clear if they are luddite...

From Computational Complexity

The Complexity of NIM. Open?

Recall 1-pile NIM: Let A be a finite set of Naturals. NIM(A) is the following game: There are n stones on the board. Players I and II alternate removing a\in A...

From Computational Complexity

Dagstuhl on Algebra in Computational Complexity

(Reminder- Theory day at UMCP: here is the link. ) There was a Dagstuhl on Algebra in Computational Complexity Sept 22-26. I learned stuff in the talks, over meals...

From Computational Complexity

Gentry and Lurie and Zhang can say they are genius's without bragin'- MacArthur Genius's

(If I mispell anything in this post, well, that"s why I'm not a MacArthur Genius, or any other kind of Genius.) Craig Gentry, of homomorphic encryption fame, won...

From Computational Complexity

Maryland Theory Day October 10!

Univ of Maryland at College Park is having a Theory Day Friday October 10. Free Registration and Free Lunch! (there are no economists coming to tell us therehere...

From Computational Complexity

A Statistical oddity ?

 I keep a list of people that are famous-to-me  that are old so that if someone dies I won't be surprised. When Lauren Bacall died  recently I  (1) knew who she...

From Computational Complexity

How hard is changing fields? Ask Sheldon!

In the last season of  The Big Band Theory Sheldon wants to change field from String theory to something else (I don't recall if he settled on what it would be,...

From Computational Complexity

Quetions that arose teaching HS students crypto

I taught a 3-week, 3-hours-a-day course to HS student titled Computer Science: A Hands Off Approach. Given that time constraints and the fact that some already...

From Computational Complexity

The n^{1/3} barrier for 2-server PIR's broken! A lesson for us all!

Recall: PIR stands for Private Information Retrieval. Here is the model: A database is an n-bit string (my wife tells me this is not true). The user wants to find...

From Computational Complexity

How I know Moneyball is a true story. Do we clean up theorems and life too much?

A few years ago I saw the movie Moneyball about how the Oakland A's used intelligent statistics to... win? No, but to do better-than-expected.  Even if I didn't...

From Computational Complexity

How NOT to bet

(True Story, but names are changed for no good reason.) Alice, Bob, and Carol are betting on who will be the Republican Nominee in 2016. Alice bets on Jeb Bush...

From Computational Complexity

The Change Problem and the Gap between Recreational and Serious Mathematics

In a prior post (here)I discussed the change problem: given a dollar, how many ways can you make change using pennies, nickels, dimes, and quarters (and generalize...

From Computational Complexity

Need some book reviewed- faster than usual

I have been the SIGACT NEWS book review editor since 1997. I have tried to get about 10 books reviewed per column. I have succeeded- perhaps too well! I have gotten...

From Computational Complexity

What to call the top and bottom part of (n choose k)

In my last post I asked for candidates for names for the top and bottom part of (n choose k) . Here are the candidates and my comments on them and ... the winner...

From Computational Complexity

Is there a word for the top part of a binomial coefficient?

Consider the sequence: x/y,  (x+1)/y, (x+2)/y, ..., (x+z)/y one could say  in this sequence of fractions the numerators goes through z-1 consecutive numbers. ...

From Computational Complexity

3000 lunches

Last week fortune smiled on two of my friends: Ken Regan made the cover of Chess Life for his work on catching chess cheaters. (See here.) Jacob Lurie who I mentored...

From Computational Complexity

How many ways can you make change of n cents?

(For a related post see  my post on Schur's theorem. The paper THIS post refers to is  here.) (ADDED LATER: A commenter pointed to Graham-Knuth-Patashnik forhere...

From Computational Complexity

Ref/info request for an obvious approach to GI

Talking about Graphi Isom with some students they came up with the following idea which is certainly not new; however, I couldn't quite find much about it on the...

From Computational Complexity

Fair question? Trick question?

The following problem was on my final for Formal Lang theory (Reg, P, NP, Dec, c.e.) For this problem you may assume P\ne NP and NP\ne coNP. For each of the following...
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