Sunday, August 29, 2010

Bridge not out

Speaking of government not working well, this isn't the biggest deal in the world but it is starting to annoy me. The Quaker Bridge Road Bridge repairs took longer than they were supposed but they were finished months ago and the bridge was reopened. It is time someone took down the sign.

Saturday, August 28, 2010

Public Servants

Matthew Yglesias responding to a rant about the DMV by Keith Humpheys makes a point with has also occurred to me. Namely that liberals who want a society with a bigger role for government should worry more about making government work well than they do. People are naturally reluctant to give more responsibilities to an entity that doesn't appear to be handling its current responsibilities well.

Wednesday, August 18, 2010

Complexity theory update

I was asked in comments about the claimed P != NP proof I posted about last week. This NYT article has a reasonable summary of current opinion. Basically the "proof" appears to have some serious problems. Unfortunately the author may have trouble accepting this verdict.

As for what a proof would mean, the bare fact alone would not change much since many people already assume it is true. However it is likely a valid proof would depend on much greater insight into the theory computation than we currently have.

Tuesday, August 17, 2010

Housing markets

One of the Congressmen I find most irritating, Barney Frank, was in the news yesterday continuing to spout nonsense about the housing market:

“We’ve already abolished Fannie and Freddie,” he said, referring to the government takeover. “Yes, we waited too long to fix it. But the money is not being lost by anything they are doing now.”

This is simply wrong. As the article acknowledges the government is propping up the housing market by providing subsidized mortgages. But subsidized is just another way of saying money losing. Perhaps under the circumstances there is something to be said for this policy (although I oppose it). But pretending it is not costing the government money is dishonest. And they haven't "fixed" anything.

Also it is easy to underestimate the perverse effects of government subsidies. I might currently be in the market for a house but I am reluctant to enter a market in which I would be competing with people playing with government money, no money down government backed loans that they can easily walk away from if prices move against them.

Saturday, August 14, 2010

Butterfly Garden

I went walking in Pruyn Sanctuary again today. The highlight for me was the butterfly garden near the Route 133 entrance. Apparently a butterfly garden consists of plants chosen to attract butterflies. This one was quite successful today, the picture shows one of the many butterflies.

Tuesday, August 10, 2010

Alternating sequences

Last week I heard a talk by Richard Stanley in which he mentioned a version of the following problem. Define an alternating sequence as one in which the differences between adjacent elements are alternatively positive and negative. So 1,2,3 and 3,2,1 are not alternating sequences but 1,4,2,5,3,6 is. Consider random permutations of 1,2,...,n. We ask as n goes to infinity what is the expected length of the longest alternating subsequence? Note the elements of a subsequence do not have to be adjacent in the original sequence. You can think of a subsequence as what is left after you delete some elements of a sequence.

Sunday, August 8, 2010

Big news in complexity theory?

An HP researcher, Vinay_Deolalikar , is claiming to have proved that P != NP. This is of course a major result if correct. I would guess the odds are it isn't but an expert thinks it is worth taking seriously. I glanced through the preliminary version of the paper. It goes well beyond my superficial knowledge of complexity theory so I will defer to more expert opinion as to correctness. I expect this will be forthcoming fairly quickly.

Sunday, August 1, 2010

Labor markets

Matthew Yglesias writing about how more education can reduce the wage gap between skilled and unskilled workers by increasing the supply of skilled workers and decreasing the supply of unskilled workers:

There are a lot of things going on here, but one point to keep in mind is that progress in educational attainment is generally beneficial not just beneficial to the people who get the extra education. Insofar as more Finnish people acquire skills and learn to be cell phone company executives or furniture designers or Finnair pilots that’s (a) more income to be spent on goods and services produced by lower-skilled people and (b) fewer lower-skilled people to compete for those jobs. Consequently, the Finnish people who don’t upgrade their skills also benefit from the fact that other Finnish people have been upgrading. Consequently, the great expansion in educational opportunities in the 1870-1970 era helped produce prosperity even for people like Connie Freeman’s dad who didn’t necessarily personally acquire a great deal of education.

This makes a certain amount of sense. But of course when it comes to the effects of immigration on wages Yglesias no longer believes in the negative effects of increased supply predicted by simple models (or perceived by those directly affected).