Search found 1798 matches

by btilly
Fri Oct 31, 2008 2:03 am UTC
Forum: Mathematics
Topic: Inclusion/Exclusion Principle in Prime Sieving?
Replies: 3
Views: 2228

Re: Inclusion/Exclusion Principle in Prime Sieving?

First an inclusion-exclusion example. Suppose you want to know the number of numbers less than 1000 that are relatively prime to 2, 3, and 5. Inclusion-exclusion says that it is: 1000 - floor(1000/2) - floor(1000/3) - floor(1000/5) + floor(1000/6) + floor(1000/10) + floor(1000/15) - floor(1000/30) I...
by btilly
Mon Oct 13, 2008 7:16 pm UTC
Forum: Mathematics
Topic: BA or BSc?
Replies: 19
Views: 3713

Re: BA or BSc?

Despite attacking ancillary points, nobody disagreed with my prior assertion that GIVEN THE CHOICE BETWEEN BS and BA at a school offering both degrees (such as the OP's situation!)...BS is equally or more rigorous than the BA. This obviously does not apply where a school has only one option, histor...
by btilly
Mon Oct 13, 2008 7:03 pm UTC
Forum: Science
Topic: Heisenberg Uncertainty Principle (merged threads)
Replies: 35
Views: 5262

Re: Uncertainty Principle

Thank you BlackSails for knowing your physics. btilly: no. You just described the properties of the probabilistic nature of quantum. That has nothing to do (explicitly) with the precision of a measurement, just where you can possibly find the particle. Uncertainty principle involves characteristics...
by btilly
Fri Oct 10, 2008 6:15 pm UTC
Forum: Mathematics
Topic: BA or BSc?
Replies: 19
Views: 3713

Re: BA or BSc?

I've never heard of a case where the BA was more rigorous than the BS. Thus, if I were hiring graduates, or sitting on an admissions board, I would favor the BS. I had friends in school who were getting a BA in the course where I got a BS. They did not have to take any "real" math, "...
by btilly
Fri Oct 10, 2008 1:08 am UTC
Forum: Serious Business
Topic: Assassination markets
Replies: 52
Views: 6236

Re: Assassination markets

Ethics aside, I have one point that no one brought up - how would we confirm the 'identity' of the assassins? The same veil of anonymity that allows them to collect their money anonymously would obviously bring about people who would, once hearing of a successful murder, try and claim the reward fo...
by btilly
Fri Oct 10, 2008 12:25 am UTC
Forum: General
Topic: Blood donation poll
Replies: 162
Views: 14357

Re: Blood donation poll

This is maybe to do with BSC? I'm not sure. Even still, I think it points out how arbitrary the rules on giving blood can be. If the UK were to adopt the same rule, then we'd have almost no blood supply at all. I think you meant BSE, aka mad cow. The probable reason for a lifetime ban in Canada is ...
by btilly
Thu Oct 09, 2008 11:49 pm UTC
Forum: General
Topic: Blood donation poll
Replies: 162
Views: 14357

Re: Blood donation poll

By that logic, a woman having anal sex with a man ('even once') should be equally worth of disqualification. It doesn't leave any room for gay male couples in long-term/permanent relationships, neither of whom has HIV. I don't think that is particularly unfair in the case of monogamous gays, becaus...
by btilly
Thu Oct 09, 2008 6:36 am UTC
Forum: General
Topic: Blood donation poll
Replies: 162
Views: 14357

Re: Blood donation poll

By that logic, a woman having anal sex with a man ('even once') should be equally worth of disqualification. It doesn't leave any room for gay male couples in long-term/permanent relationships, neither of whom has HIV. I don't think that is particularly unfair in the case of monogamous gays, becaus...
by btilly
Wed Oct 08, 2008 6:54 pm UTC
Forum: Serious Business
Topic: Assassination markets
Replies: 52
Views: 6236

Re: Assassination markets

My question is whether the market could really work as described in the article. The article makes three assumptions: 1. This is something that ought to be done. 2. This can be done in a way that preserves anonymity for all involved. 3. This can be done in such a way that the existence of the marke...
by btilly
Tue Oct 07, 2008 11:11 pm UTC
Forum: Serious Business
Topic: Assassination markets
Replies: 52
Views: 6236

Re: Assassination markets

Well, apart from being illegal, dependent upon a non-existent untraceable virtual money, likely to be fought on a moral ground, there is no technical flaw, indeed. You are missing some background. At the time that article was written cryptographic protocols had been created that allow people to cre...
by btilly
Tue Oct 07, 2008 10:59 pm UTC
Forum: Mathematics
Topic: Acceleration troubles
Replies: 9
Views: 1410

Re: Acceleration troubles

Now I'm pretty sure (but I could be wrong) that to figure this out you need to involve a velocity time graph for the two skiers, and find the point where the distances are equal... and you do that by doing something involving equations to get them to be the same. That is your mistake. You don't wan...
by btilly
Tue Oct 07, 2008 3:18 pm UTC
Forum: Serious Business
Topic: Assassination markets
Replies: 52
Views: 6236

Re: Assassination markets

That this process is inherently non-democratic is a description of how this type of market naturally works, and is not an implementation flaw to be fixed. Since when was it accepted that if you could create a natural market for something, then it had to be a good thing ? There are markets for organ...
by btilly
Tue Oct 07, 2008 1:34 am UTC
Forum: Science
Topic: Heisenberg Uncertainty Principle (merged threads)
Replies: 35
Views: 5262

Re: Uncertainty Principle

Uncertainty principle doesn't really apply to a single experiment. If you were to measure position and momentum, it's not like the computers would tell you "Nope, sorry, I can't give you that number because of the uncertainty principle." No. You'd get a perfectly fine value for position a...
by btilly
Tue Oct 07, 2008 1:22 am UTC
Forum: Mathematics
Topic: Simultaneous equations
Replies: 11
Views: 1544

Re: Simultaneous equations

With those prices I predict a shortage of milk and a fire sale on mutton in a few years. For some things it is best just to do a brute force search. This is one of them. As a hint, I will tell you that there are 2 answers. I suspect that if you read the problem closely, you'll find that you need to ...
by btilly
Tue Oct 07, 2008 1:12 am UTC
Forum: Mathematics
Topic: BA or BSc?
Replies: 19
Views: 3713

Re: BA or BSc?

I can only answer this from my experience in Canada and the USA. I have a BSc in math from the University of Victoria in Canada, and an AM degree in math from Dartmouth College in the USA. I didn't quite finish my PhD because of financial constraints. (This state is often jokingly referred to as PhD...
by btilly
Tue Oct 07, 2008 12:24 am UTC
Forum: Serious Business
Topic: Assassination markets
Replies: 52
Views: 6236

Re: Assassination markets

I find it interesting that people's reactions to, "This market would naturally work in a way that I don't like" tends to be to twerk the market to work like you would like it to work. The market described has a natural way it wants to work, and if there is demand for it, there will be dema...
by btilly
Mon Oct 06, 2008 11:12 pm UTC
Forum: Serious Business
Topic: Assassination markets
Replies: 52
Views: 6236

Re: Assassination markets

Is anybody else reminded of DARPA's ill-fated proposal for a Policy Analysis Market ? Interesting parallel. Except that in the policy analysis market the market's interplay with the actors in the system was an unexpected consequence, while in the assassination market it is the point of the whole sy...
by btilly
Mon Oct 06, 2008 11:11 pm UTC
Forum: Science
Topic: clearing up some misconceptions about chaos
Replies: 6
Views: 1190

Re: clearing up some misconceptions about chaos

First a little rumor control. First of all it is wrong that the 3 problem is not solvable analytically. It can be solved analytically (as can the general n-body problem), but it can't be done in terms of elementary functions. And the analytic solutions converge extremely slowly. I'm sure I won't be ...
by btilly
Mon Oct 06, 2008 10:25 pm UTC
Forum: Serious Business
Topic: Assassination markets
Replies: 52
Views: 6236

Re: Assassination markets

I'm surprised that this one had not been discussed here a long time ago. I don't know how many years ago I ran across it. Um. There are a number of problems with this: 1. It's wrong to kill people because you don't like their policies. Possible exception: they are going to have you killed if you don...
by btilly
Mon Oct 06, 2008 9:57 pm UTC
Forum: Mathematics
Topic: Completely distributive lattice
Replies: 3
Views: 1294

Re: Completely distributive lattice

How much are you willing to pay me to do your homework and deny you the opportunity to learn?
by btilly
Mon Sep 22, 2008 6:55 pm UTC
Forum: Coding
Topic: Coding: Fleeting Thoughts
Replies: 10016
Views: 2033147

Re: Coding: Fleeting Thoughts

I started research on lazy evaluation in python, but didn't get very far. I've got an idea, but it's going to take me a few hours at least. You might like Infinite lists in Perl . The techniques described there of using closures to lazily generate infinite data structures should translate very easi...
by btilly
Sun Sep 21, 2008 5:10 am UTC
Forum: News & Articles
Topic: Merill Lynch, Lehman Brothers collapse
Replies: 61
Views: 5523

Re: Merill Lynch, Lehman Brothers collapse

OK, so now we're going to blow twice what the Iraq war has cost. My concern is whether this is the straw that makes the world reconsider whether US Treasury Bonds are a riskless investment. If they do that, then the interest rate that the US pays goes up and the US might not be able to spend an unli...
by btilly
Sun Sep 21, 2008 4:52 am UTC
Forum: Serious Business
Topic: The cause of the current financial crisis - cultural?
Replies: 36
Views: 3581

Re: The cause of the current financial crisis - cultural?

I said that the number one and two reasons are china and india. I didn't say what the number 3 and 4 reasons are. I disagree on your list. I would place China and India as #2 and #3. In #1 I would place political instability in the top oil producing area of the world, with the country with the #2 r...
by btilly
Thu Sep 18, 2008 12:42 am UTC
Forum: Mathematics
Topic: irrational numbers as typewriting monkeys
Replies: 41
Views: 4718

Re: irrational numbers as typewriting monkeys

To be more precise, I meant the set \{x \in 2^\omega : K(n)-K(x |_n) \text { is unbounded}\} has measure 0. (Here x | n denotes the string consisting of the first n bits of x , and K is prefix-free Kolmogorov complexity.) If that is meant to be an easy to understand restatement of w...
by btilly
Wed Sep 17, 2008 3:51 pm UTC
Forum: Science
Topic: Where can I see the curvature of the Earth?
Replies: 24
Views: 4726

Re: Where can I see the curvature of the Earth?

I follow the line of reasoning, and calculated the distance to the horizon at a variety of distances. I did not want to approximate, so I wound up with arccos[r/(r+h)]*r . I wanted to know at what altitude can you see the entire disk of the earth (h=2r). The answer from the equation is nons...
by btilly
Tue Sep 16, 2008 9:25 pm UTC
Forum: Serious Business
Topic: Homosexual Marriage?
Replies: 394
Views: 36471

Re: Homosexual Marriage?

Why should we have to give up the word "marriage", which has the universal meaning of being united, to religious institutions? Marriage is not a religious institution in origin; it is a civil contract, as created by the Romans. Not exactly. The oldest form of marriage that we have documen...
by btilly
Tue Sep 16, 2008 9:01 pm UTC
Forum: Mathematics
Topic: irrational numbers as typewriting monkeys
Replies: 41
Views: 4718

Re: irrational numbers as typewriting monkeys

That's one reason why it's a bad idea to conflate "normal" with "random" - random numbers are all normal (at least in the sense that the non-normal numbers have measure 0), but not all normal numbers should be considered random. I still want to correct you with "random numb...
by btilly
Tue Sep 16, 2008 4:32 pm UTC
Forum: Science
Topic: 'Acoustic Lensing'
Replies: 15
Views: 2907

Re: 'Acoustic Lensing'

By the way, focusing sound is the same problem as focusing light, you're bound by wavelength and focal length. Basically, you can't focus a wave on a zone smaller than half a wavelength. There are tricks to go below that, but not by much. As http://en.wikipedia.org/wiki/Superlens explains, it is th...
by btilly
Tue Sep 16, 2008 4:11 am UTC
Forum: General
Topic: Blood donation poll
Replies: 162
Views: 14357

Blood donation poll

viewtopic.php?f=2&t=27578 made me curious what people's blood donor status was. Hence this poll.
by btilly
Tue Sep 16, 2008 1:08 am UTC
Forum: Serious Business
Topic: Homosexual Marriage?
Replies: 394
Views: 36471

Re: Homosexual Marriage?

It seems that many in this thread have no idea of the complexities of marriage historically. It is simply historically incorrect to say that marriage is a religious institution. Through history as far back as can be recorded, marriage has been a recognized phenomena with widely varying rules, and ex...
by btilly
Mon Sep 15, 2008 10:54 pm UTC
Forum: Mathematics
Topic: irrational numbers as typewriting monkeys
Replies: 41
Views: 4718

Re: irrational numbers as typewriting monkeys

If you had 5 digits and you looked at all substrings of length 6 (empty set), every substring would be equally likely. That's what I meant by that part. Attempting brevity last night, I worded this request very badly. I thought people would know what I meant. Looking at it now, even I don't know wh...
by btilly
Mon Sep 15, 2008 5:57 am UTC
Forum: Serious Business
Topic: Should children be trained in combat and fighting?
Replies: 78
Views: 8404

Re: Should children be trained in combat and fighting?

you know, maybe I've missed it, but I haven't seen anybody point out a basic point about empathy. Namely, if you let, say, 8 year old boys fight, they find out that it hurts. It hurts to get hit. It hurts to hit, even if you do it right. really, i'd be all in favor of letting every 8 year old boy g...
by btilly
Mon Sep 15, 2008 5:08 am UTC
Forum: Mathematics
Topic: irrational numbers as typewriting monkeys
Replies: 41
Views: 4718

Re: irrational numbers as typewriting monkeys

Wow. It's funny that we can calculate the digits of pi without knowing all of their properties. Incidentally, how do they calculate pi? Is there some nice formula like there is for e like \lim_{n\rightarrow \infty}(1+\frac{1}{n})^n that they can keep reevaluating for higher and higher preci...
by btilly
Fri Sep 12, 2008 3:47 pm UTC
Forum: Serious Business
Topic: Should children be trained in combat and fighting?
Replies: 78
Views: 8404

Re: Should children be trained in combat and fighting?

The analogy would only hold if giving one child bread caused another child to get physically injured. Obviously with bread that is not the case. However with martial arts, that's a very valid concern. Particularly given the realities of bullying in schoolyards. Come on, stop that, already. Martial ...
by btilly
Fri Sep 12, 2008 12:10 am UTC
Forum: General
Topic: Donating Blood
Replies: 43
Views: 4095

Re: Donating Blood

Not letting gay men give blood is ridiculous. It's not the fault of any organization that collects the blood, it is required by the FDA. Yet another example of government sponsored discrimination against homosexuals. It makes me really not want to give blood, but I can't really justify denying bloo...
by btilly
Thu Sep 11, 2008 11:56 pm UTC
Forum: Mathematics
Topic: irrational numbers as typewriting monkeys
Replies: 41
Views: 4718

Re: irrational numbers as typewriting monkeys

Wow. It's funny that we can calculate the digits of pi without knowing all of their properties. Incidentally, how do they calculate pi? Is there some nice formula like there is for e like \lim_{n\rightarrow \infty}(1+\frac{1}{n})^n that they can keep reevaluating for higher and higher preci...
by btilly
Thu Sep 11, 2008 10:38 pm UTC
Forum: General
Topic: Donating Blood
Replies: 43
Views: 4095

Re: Donating Blood

The rationale for not paying for blood donation is that when you create incentives to donate, you create incentives to lie about being qualified to donate. Many of the conditions that they test for (eg AIDS) won't show up on tests right away but still can cause problems. Therefore honest answers are...
by btilly
Thu Sep 11, 2008 10:24 pm UTC
Forum: Science
Topic: 'Acoustic Lensing'
Replies: 15
Views: 2907

Re: 'Acoustic Lensing'

It's certainly possible, though. I don't remember where I was when I saw it, but there was some very cool place with pictures or videos or something, and these strange plastic hemispheres suspended from the ceiling above them. When you stood directly below the hemisphere, you could hear the sound a...
by btilly
Thu Sep 11, 2008 3:11 am UTC
Forum: Serious Business
Topic: Should children be trained in combat and fighting?
Replies: 78
Views: 8404

Re: Should children be trained in combat and fighting?

This is absolutely a horrible idea. Growing up I had a significant coordination problem. The left and right sides of my brain have limited communication. This makes it harder to learn any skill where you have to coordinate the two sides of your body. I can actually learn to do anything anyone else ...
by btilly
Thu Sep 11, 2008 12:46 am UTC
Forum: Site/Forum issues
Topic: What is my new rank?
Replies: 7
Views: 1731

Re: What is my new rank?

Right. Do what you want with the silly forum games and memes, but please leave me out of it unless I volunteer to take part.

I'm terribly sorry, but that's not quite how it works...

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