## Search found 212 matches

- Wed Sep 06, 2017 1:55 pm UTC
- Forum: Individual XKCD Comic Threads
- Topic: 1886: Typing Notifications
- Replies:
**18** - Views:
**4500**

- Wed Jun 14, 2017 3:02 pm UTC
- Forum: Individual XKCD Comic Threads
- Topic: 1850: "Air Force Museum"
- Replies:
**14** - Views:
**4706**

### 1850: "Air Force Museum"

https://imgs.xkcd.com/comics/air_force_museum.png Title text: "I had fun visiting the museum at Dover Air Force Base, unless they don't have a museum, in which case I've never been to Delaware in my life." Writing this from the Early Twenty-First Century Workplace Museum, where we get to ...

- Tue Jul 21, 2015 4:10 pm UTC
- Forum: Individual XKCD Comic Threads
- Topic: 1553: "Public Key"
- Replies:
**19** - Views:
**7360**

### Re: 1553: "Public Key"

Oh yeah, I did say that, didn't I.

Good point.

Good point.

- Tue Jul 21, 2015 3:19 pm UTC
- Forum: Individual XKCD Comic Threads
- Topic: 1553: "Public Key"
- Replies:
**19** - Views:
**7360**

### Re: 1553: "Public Key"

Signatures are often hidden by default - either by the mail client or by the recipient's own wetware - so using the for content is a bit optimistic... The signature I'm talking about doesn't really have anything to do with a 'signature' in the sense of a human-readable statement at the end of the e...

- Tue Jul 21, 2015 2:39 am UTC
- Forum: Individual XKCD Comic Threads
- Topic: 1553: "Public Key"
- Replies:
**19** - Views:
**7360**

### Re: 1553: "Public Key"

Why have I sent two PGP signed messages in the multi-year lifespan of my email address and key identity? I'm pretty sure that's on you. I sign every outgoing email I send. Admittedly this is partially a one-man awareness campaign on my part---I look forward to the occasions when someone asks "...

- Wed Feb 18, 2015 4:41 pm UTC
- Forum: Mathematics
- Topic: 10% x5 != 50%?
- Replies:
**17** - Views:
**4638**

### Re: 10% x5 != 50%?

There's a term for that ... basically, probability gets a little imprecise when infinities are involved, and you can technically draw a distinction between "probability zero but technically possible" vs "actually impossible". Like, "I flip a coin an infinite number of times...

- Wed Mar 06, 2013 5:37 am UTC
- Forum: Mathematics
- Topic: Polynomial regression with a complexity prior
- Replies:
**9** - Views:
**2812**

### Re: Polynomial regression with a complexity prior

I'm not quite sure I'm following some of the maths there. Can I just check? Sure! The point I may not have made explicit enough is that I'm describing a general procedure first, and *then* describing how it applies (or fails to apply) to polynomials in particular. So this prior is over all function...

- Mon Mar 04, 2013 3:16 am UTC
- Forum: Mathematics
- Topic: Polynomial regression with a complexity prior
- Replies:
**9** - Views:
**2812**

### Re: Polynomial regression with a complexity prior

I've just realized a problem with trying to work entirely from theory. In theory, if you want to do everything from first principles, you can work as follows: ⋅ Start with a space of functions F together with a prior probability measure π. ⋅ Take some probability density function...

- Mon Mar 04, 2013 12:28 am UTC
- Forum: Mathematics
- Topic: Polynomial regression with a complexity prior
- Replies:
**9** - Views:
**2812**

### Re: Polynomial regression with a complexity prior

I've just realized something: if I prefer a lower-degree polynomial, I probably oughtn't to also prefer a lower number of nonzero coefficients within a polynomial, because that criterion amounts to privileging the standard parameterization. (Actually, I think the really right thing to do would be to...

- Sat Mar 02, 2013 8:46 pm UTC
- Forum: Mathematics
- Topic: Polynomial regression with a complexity prior
- Replies:
**9** - Views:
**2812**

### Polynomial regression with a complexity prior

Hey, I have absolutely no formal training in statistics, though I know a bit more about probability and information theory. My interest here is more from an academic than a practical standpoint. Suppose I have some data in the form of points of ℝ², and i want to fit a polynomial to these points. And...

- Thu Mar 29, 2012 3:43 pm UTC
- Forum: Forum Games
- Topic: Random bitstream! (000zerozero000000zero)
- Replies:
**1947** - Views:
**234551**

- Thu Mar 22, 2012 4:53 am UTC
- Forum: Science
- Topic: Most recent common ancestor between strangers?
- Replies:
**22** - Views:
**7796**

### Re: Most recent common ancestor between strangers?

There is a mountain of evidence for this. The most obvious being that every living thing has the same genetic code. The same amino acids are used. I remember reading somewhere that this is only almost true: a few species of microörganism have been discovered that have variant genetic codes . These ...

- Tue Mar 20, 2012 4:25 pm UTC
- Forum: Serious Business
- Topic: Do the ends justify the means?
- Replies:
**74** - Views:
**13721**

### Re: Do the ends justify the means?

I don't know why you're treating this like I'm part of some grand leading-question conspiracy to convince you that it's OK to shove people in front of trains.... etc. Sorry, I don't actually think you're doing that, at least not deliberately. I just think it's all the question is really useful for ...

- Tue Mar 20, 2012 3:35 pm UTC
- Forum: Mathematics
- Topic: Infinity paradox? Help
- Replies:
**54** - Views:
**9318**

### Re: Infinity paradox? Help

In addition to the above objections, even if you create some self-consistent system of arbiteroftruth-integers, some of which have infinitely many digits, I can still say "consider the set of all arbiteroftruth-integers with finitely many digits" and once again have an infinite set, all of...

- Tue Mar 20, 2012 5:21 am UTC
- Forum: Serious Business
- Topic: Do the ends justify the means?
- Replies:
**74** - Views:
**13721**

### Re: Do the ends justify the means?

TheGrammarBolshevik, I understand what you're saying. I really do. I've said it myself before, when I'm using an extreme case to put some concept or another into sharp relief and someone gets on my case because it's "unrealistic." You are saying it doesn't matter if the scenario is unreali...

- Mon Mar 19, 2012 7:26 pm UTC
- Forum: Mathematics
- Topic: Distance on a sphere
- Replies:
**14** - Views:
**4394**

### Re: Distance on a sphere

My first thought was, "What does OP mean by distance? Does he mean chordal distance or great circle distance?" (Chordal distance is the length of a straight line segment through the interior of the sphere; great circle distance is the length of the shorter of the two great circle arcs pass...

- Mon Mar 19, 2012 7:00 pm UTC
- Forum: Mathematics
- Topic: Infinity paradox? Help
- Replies:
**54** - Views:
**9318**

### Re: Infinity paradox? Help

Perhaps I should phrase it this way: Given the way I've ordered the set, the number of elements in the set cannot exceed the values that are allowed to exist within the set, because each element of the set is a value corresponding to exactly how many elements are included up to that point. So if th...

- Mon Mar 19, 2012 5:44 am UTC
- Forum: Serious Business
- Topic: Do the ends justify the means?
- Replies:
**74** - Views:
**13721**

### Re: Do the ends justify the means?

Re. the "push the fat guy in front of the train" thought experiment: If you present the situation in a vacuum, I'll interpret it in a vacuum. That is, I'll assume you're postulating that 1. I know the train's five passengers will die if I do nothing; 2. I know this guy is heavy enough to s...

- Wed Mar 14, 2012 4:22 am UTC
- Forum: Mathematics
- Topic: Pi in fraction form
- Replies:
**17** - Views:
**5312**

### Re: Pi in fraction form

I realise that there's no way to ask this question without it seeming really stupid, but I'll give it a go anyway... is there some intrinsic quality of a circle that dictates that Pi must be an irrational number or is it just 'bad luck'? It's not a stupid question at all. There is proof that π is i...

- Mon Feb 20, 2012 1:30 am UTC
- Forum: Science
- Topic: Most recent common ancestor between strangers?
- Replies:
**22** - Views:
**7796**

### Re: Most recent common ancestor between strangers?

Interactive Civilian, what do you make of the 2004 Nature article by a Yale mathematician (PDF) suggesting that the MRCA of all or nearly all living humans ought to be about 3,000 years old? Particularly since ethnic "purity" is a lot less common than most people believe---we nearly all ha...

- Sun Feb 19, 2012 8:15 pm UTC
- Forum: Science
- Topic: Most recent common ancestor between strangers?
- Replies:
**22** - Views:
**7796**

### Most recent common ancestor between strangers?

It's common knowledge that "we're all related if you go back far enough," but it's less commonly known exactly how far back is far enough. I'm guessing it's not actually that far. Obviously the degree will vary from place to place, based on cultural norms, rate of immigration/emigration, e...

- Mon Sep 19, 2011 8:25 am UTC
- Forum: Science
- Topic: Time Without Change
- Replies:
**69** - Views:
**8361**

### Re: Time Without Change

It's pretty obvious that the block-universe concept can model "everything stays really still for a while" as distinct from "no time passes." The question is whether the block-universe concept is correct in making this distinction, i.e. whether the universe is really a block in th...

- Tue Sep 13, 2011 11:08 am UTC
- Forum: Mathematics
- Topic: Resolution of Russell's and Cantor's paradoxes
- Replies:
**64** - Views:
**10647**

### Re: Resolution of Russell's and Cantor's paradoxes

Maybe if you say "logical fallacy" ten or eleven more times, one will appear.

There is no fallacy, man.

There is no fallacy, man.

- Tue Sep 13, 2011 6:23 am UTC
- Forum: Science
- Topic: Time Without Change
- Replies:
**69** - Views:
**8361**

### Re: Time Without Change

To answer the OP: I agree, it looks like "time" is emergent from the structure of the universe, not something fundamental. The idea "Suddenly the whole universe reverts to its state 2000 years ago" is confused, sort of like "Suddenly everything in the universe moves 50 meter...

- Tue Sep 13, 2011 4:52 am UTC
- Forum: Mathematics
- Topic: Resolution of Russell's and Cantor's paradoxes
- Replies:
**64** - Views:
**10647**

### Re: Resolution of Russell's and Cantor's paradoxes

Dear DanTeplitskiy, I have not reread your paper. Please don't assume, because I am not impressed, that I haven't understood. Every time someone tries to critique your work, you call it a misunderstanding and inject into your paper a little blurb that says "You might think X, but that's not tru...

- Fri Sep 09, 2011 6:23 pm UTC
- Forum: Mathematics
- Topic: Resolution of Russell's and Cantor's paradoxes
- Replies:
**64** - Views:
**10647**

### Re: Resolution of Russell's and Cantor's paradoxes

I skimmed the rest but read 12-14 a bit more closely. It seems like you have a solution in search of a problem. I'm not sure where you got the idea that mathematicians are confused by the Russell class, and are working on resolving this contradiction, but they really aren't. Your analysis of { x : x...

- Fri Sep 02, 2011 1:43 am UTC
- Forum: Forum Games
- Topic: Random bitstream! (000zerozero000000zero)
- Replies:
**1947** - Views:
**234551**

- Wed Jun 08, 2011 4:34 pm UTC
- Forum: Mathematics
- Topic: Is there an intuitive appeal for multiplication of integers?
- Replies:
**22** - Views:
**3745**

### Re: Is there an intuitive appeal for multiplication of integ

Good suggestions for appeals to intuition here. I'm tempted to suggest an appeal to associativity/commutativity/distributivity as well (you can prove that the product of negatives is positive), but I know from experience how well that usually goes. Try this: Call the first number "how many hats...

- Wed Jun 01, 2011 9:21 pm UTC
- Forum: Serious Business
- Topic: Bitcoin : Where can it fail ?
- Replies:
**326** - Views:
**176564**

### Re: Bitcoin : Where can it fail ?

I sold the 20 bitcoins to offset the cost of new computer toys that I impulse-bought earlier the same day. Dollars have the advantage of being currently accepted at BJ's Wholesale. I was considering selling more, to recover my initial expenses, but I really don't feel safe selling more than that rig...

- Wed Jun 01, 2011 1:00 am UTC
- Forum: Serious Business
- Topic: Bitcoin : Where can it fail ?
- Replies:
**326** - Views:
**176564**

### Re: Bitcoin : Where can it fail ?

Bump to point out that earlier today I sold 20 bitcoins for 9.2 US dollars apiece. The price has fallen a bit since then, and is now hovering around 8.7. Keep up with the charts at Mt Gox . In the time between buying in and now, I've read at least dozens of different explanations of why only an idio...

- Mon Apr 25, 2011 5:30 pm UTC
- Forum: Serious Business
- Topic: Bitcoin : Where can it fail ?
- Replies:
**326** - Views:
**176564**

### Re: Bitcoin : Where can it fail ?

Everyone should ignore my earlier post---I sold off a large stash of bitcoins only to see the exchange rate spike up to 1.9 or so, then settle down around 1.5 - 1.6. New plan: always follow the opposite of my impulse.

- Mon Apr 18, 2011 2:48 am UTC
- Forum: Serious Business
- Topic: Bitcoin : Where can it fail ?
- Replies:
**326** - Views:
**176564**

### Re: Bitcoin : Where can it fail ?

Well it would have been profitable for them if they'd started accepting them a few weeks ago, since the Mt Gox exchange just reached an all time high of 1.199 bitcoins to the dollar. (Actually just wanted to drop into the thread to report that, not to actually rebut what you're saying.) Anyone who s...

- Thu Apr 14, 2011 12:56 pm UTC
- Forum: Mathematics
- Topic: |i|
- Replies:
**34** - Views:
**5124**

### Re: |i|

I often catch myself calling |a+bi| the "absolute value" of a+bi, and I don't think I've ever been misunderstood by saying that (though I have been corrected, which implies that the listener knew exactly what I meant). It's a bad habit, but not seriously so. I sometimes suspect we should j...

- Mon Mar 28, 2011 5:31 pm UTC
- Forum: Serious Business
- Topic: Bitcoin : Where can it fail ?
- Replies:
**326** - Views:
**176564**

### Re: Bitcoin : Where can it fail ?

Okay, but the idea of the Bitcoin protocol is to be the bottom line, the equivalent of metal coins in the past or fancy paper today. There's no reason Visa can't issue BTC credit cards at usurious interest rates just like they do with USD now. There's no reason banks can't offer escrow services for ...

- Mon Mar 28, 2011 5:06 pm UTC
- Forum: Serious Business
- Topic: Bitcoin : Where can it fail ?
- Replies:
**326** - Views:
**176564**

### Re: Bitcoin : Where can it fail ?

What insurance does the FDIC offer if money is stolen from your wallet?

- Mon Mar 28, 2011 4:56 pm UTC
- Forum: Serious Business
- Topic: Bitcoin : Where can it fail ?
- Replies:
**326** - Views:
**176564**

### Re: Bitcoin : Where can it fail ?

The only thing broadcast in a transaction is a digitally signed expenditure. "Sniffing" won't get you any information that isn't already quite public. Though there's no obvious way of tracing a bitcoin address back to a machine, I suppose you could always hack the machine of a known holder...

- Mon Mar 28, 2011 4:00 pm UTC
- Forum: Serious Business
- Topic: Bitcoin : Where can it fail ?
- Replies:
**326** - Views:
**176564**

### Re: Bitcoin : Where can it fail ?

What research did you do? You clearly didn't do enough to realize that bitcoins aren't stored in your wallet, but only the credentials required to spend them, as has been mentioned several times in this thread. The record of which addresses hold which bitcoins is entirely stored in the blockchain. h...

- Mon Mar 28, 2011 3:29 pm UTC
- Forum: Serious Business
- Topic: Bitcoin : Where can it fail ?
- Replies:
**326** - Views:
**176564**

### Re: Bitcoin : Where can it fail ?

What would you have to do to get, say, a steady $100/month profit by generating and selling bitcoins? In the long run, you'd probably have to treat it like a full-time job. Market forces will drive difficulty to the point where it is just marginally profitable. In order to make any serious money yo...

- Mon Mar 28, 2011 1:08 pm UTC
- Forum: Serious Business
- Topic: Bitcoin : Where can it fail ?
- Replies:
**326** - Views:
**176564**

### Re: Bitcoin : Where can it fail ?

I am currently buying a substantial number of bitcoins at significantly more than my own cost of generation. I'm pretty confident they will remain stable increase in value for the next year or two, less so about their long range stability. I'll reconsider if things haven't improved in a year. In the...

- Mon Mar 28, 2011 11:56 am UTC
- Forum: Serious Business
- Topic: Bitcoin : Where can it fail ?
- Replies:
**326** - Views:
**176564**

### Re: Bitcoin : Where can it fail ?

I started paying attention to Bitcoin a few weeks ago, and started mining shortly thereafter. (I'd wanted a new video card anyway---this was just an excuse to buy the best one. Maybe it'll pay for itself!) I'm really becoming interested in seeing the project succeed, because it would just be so usef...