Search found 98 matches

by Fafnir43
Mon Aug 03, 2009 3:53 pm UTC
Forum: Mathematics
Topic: Math Books
Replies: 379
Views: 282634

Re: Math Books

I found a copy of Lebesgue Integration in Euclidean Space in the maths department library - after reading the first chapter and a half, it looks perfect. Thanks!
by Fafnir43
Thu Jul 30, 2009 11:14 pm UTC
Forum: Mathematics
Topic: Math Books
Replies: 379
Views: 282634

Re: Math Books

Can anyone recommend a good book on measure theory for a (soon to be) third year undergraduate? I've been recommended Taylor, but I'm having a tough time getting through it. This is for self-study in preparation for a course next year, so I'd rather have something accessible and light than something...
by Fafnir43
Sun Jun 14, 2009 7:42 pm UTC
Forum: Mathematics
Topic: What do you do when you're really struggling with math?
Replies: 10
Views: 1769

Re: What do you do when you're really struggling with math?

It's cliche, but there's really no one way to deal with hard problems - it all depends on you. That said, I've found the following quite helpful as a current undergraduate: - Work on several problems at once. When you run into serious difficulties with one problem, move onto the next and let it stew...
by Fafnir43
Sun Jun 07, 2009 12:41 pm UTC
Forum: Mathematics
Topic: Supremum and infimum over C
Replies: 12
Views: 1575

Re: Supremum and infimum over C

I've seen two of those concepts before, actually. That partial ordering on R^n was used in the linear programming section of an optimisation course I went to, and I think it's standard notation in the subject. (Basically it lets you specify a set of linear constraints on x in the form A\mathbf{x} \l...
by Fafnir43
Mon Apr 27, 2009 12:54 pm UTC
Forum: News & Articles
Topic: Sean Hannity volunteers to be waterboarded
Replies: 75
Views: 9170

Re: Sean Hannity volunteers to be waterboarded

Does anyone know what Sean Hannity's favourite charity is? I'd like to sign up for this, but I have a feeling it'll be something like Focus on the Family or worse.
by Fafnir43
Sat Apr 25, 2009 4:28 pm UTC
Forum: Mathematics
Topic: Residue Calculus Problem
Replies: 16
Views: 2648

Re: Residue Calculus Problem

By the way, handy LaTeX tip: if you use \left( and \right) instead of ( and ) the brackets will scale to fit whatever's inside them, so you can get this: \left(\frac{a}{b}\right) rather than this: (\frac{a}{b}) by using \left(\frac{a}{b}\right) rather than (\frac{a}{b}). Took me a wh...
by Fafnir43
Sun Apr 12, 2009 12:28 pm UTC
Forum: Mathematics
Topic: Interesting (maybe easy?) graph theory problem
Replies: 5
Views: 1067

Re: Interesting (maybe easy?) graph theory problem

Now that's what I call an elegant answer - thanks! Kirchhoff's theorem is magnificent - can't wait for graph theory next year...
by Fafnir43
Sun Apr 12, 2009 12:25 pm UTC
Forum: Mathematics
Topic: Math Books
Replies: 379
Views: 282634

Re: Math Books

Div, Grad, Curl and All That is for vector calculus rather than general multivariable calculus. I remember it as being very, very good at explaining concepts, but not making any effort at all to do more than that - no exercises, no rigor, very few proofs. It also explains things in terms of electrom...
by Fafnir43
Sat Apr 11, 2009 11:51 pm UTC
Forum: Mathematics
Topic: Interesting (maybe easy?) graph theory problem
Replies: 5
Views: 1067

Interesting (maybe easy?) graph theory problem

Consider an nxn grid of rooms, each of which has four possible exits - north, east, south and west. Some of these exits are blocked off. Every room is accessible from every other room, and there are no loops (i.e. if you walk around the grid starting and finishing at room x, then you must have visit...
by Fafnir43
Wed Nov 05, 2008 3:13 pm UTC
Forum: News & Articles
Topic: California proposition 8 is very close
Replies: 222
Views: 16117

Re: California proposition 8 is very close

And I AM liberal, but I also want to say (rant) that I'm really tired of people thinking that conservative=braindead. They have reasons for being conservative. You might not agree with them, I don't, and that's fine, that's why you get a vote...but I wish people would recognize that the issues are ...
by Fafnir43
Sat Oct 18, 2008 2:55 pm UTC
Forum: Mathematics
Topic: Balls in balls in R^n
Replies: 25
Views: 4226

Re: Balls in balls in R^n

Yup, turns out the problem was wrong. The corrected version now reads as follows: For this question we work in R^n with the Euclidean metric. Show that there do not exist two disjoint closed unit balls inside any closed ball of radius 2. Show that there do, however, exist (1+c)^n disjoint closed uni...
by Fafnir43
Sun Sep 07, 2008 2:25 pm UTC
Forum: Mathematics
Topic: ...How do i factor
Replies: 9
Views: 1438

Re: ...How do i factor

I'd multiply it all out first. Then you should be able to factor it up nicely. Multiplying that out would be a bad idea unless you can factor 6x^4 - 24x^3 - 33x^2 - 12x - 18. What exactly would i be multiplying?.. im so sorry.. i must seem useless "Multiplying it out" is a general term fo...
by Fafnir43
Sun Sep 07, 2008 11:51 am UTC
Forum: Mathematics
Topic: Balls in balls in R^n
Replies: 25
Views: 4226

Re: Balls in balls in R^n

Sure thing, although it'll probably be in about a month's time.
by Fafnir43
Sun Sep 07, 2008 1:59 am UTC
Forum: Mathematics
Topic: Balls in balls in R^n
Replies: 25
Views: 4226

Re: Balls in balls in R^n

PS: The OP should put "... closed unit balls..." in the first problem, for posterity :P Whoops... :oops: Fixed now. PS. Wait, the text says balls, not spheres. Does that mean we are trying to fit lumps of plasticine into a sphere? "Ball" is a standard term when dealing with metr...
by Fafnir43
Sat Sep 06, 2008 4:54 pm UTC
Forum: Mathematics
Topic: Balls in balls in R^n
Replies: 25
Views: 4226

Balls in balls in R^n

In R^n under the Euclidean metric, show that there do not exist two disjoint closed unit balls inside any closed ball of radius 2. Show that there do, however, exist (1+c)^n disjoint closed unit balls inside any closed ball of radius 2.001, for some absolute constant c > 0. I've been squinting at th...
by Fafnir43
Thu Aug 28, 2008 9:10 pm UTC
Forum: Coding
Topic: Help Wanted
Replies: 36
Views: 83327

Re: Empowering Consumers

First Post. So for those who aren't familiar with the concept of Decentralized Democracy, it is this: Ensuring as much of 'the vote' is in the hand of each citizen as possible, and ensuring that decision-making leaders are held closely to those they represent. (A politician writes the best law that...
by Fafnir43
Wed Aug 27, 2008 2:15 am UTC
Forum: Coding
Topic: Complexity of library functions in Python
Replies: 2
Views: 1302

Re: Complexity of library functions in Python

That is useful - thanks. I did actually google "python complexity", "python library complexity" and a few variants thereof and got very little - mostly forum posts asking about specific functions. About the closest I got to a general reference was this post , in which someone ask...
by Fafnir43
Tue Aug 26, 2008 4:47 pm UTC
Forum: Coding
Topic: Complexity of library functions in Python
Replies: 2
Views: 1302

Complexity of library functions in Python

Recently I've been working on some coursework in Python, and I've been having some difficulty finding the time complexities of common library functions - they don't really seem to be documented. Sometimes this has almost tripped me up - for example, Python's "lists" are apparently represen...
by Fafnir43
Thu Jul 10, 2008 9:11 pm UTC
Forum: Mathematics
Topic: Is this a metric?
Replies: 7
Views: 1954

Re: Is this a metric?

Thanks!
by Fafnir43
Wed Jul 09, 2008 12:28 pm UTC
Forum: Mathematics
Topic: Is this a metric?
Replies: 7
Views: 1954

Re: Is this a metric?

The statement that D is a metric, or the statement that ||(x_1, ..., x_n)|| <= ||(y_1, ..., y_n)|| when x_i <= y_i for all i?
by Fafnir43
Tue Jul 08, 2008 6:35 pm UTC
Forum: Mathematics
Topic: Is this a metric?
Replies: 7
Views: 1954

Is this a metric?

This is a homework question, but I've been beating my head against it for too long so I'm coming here to beg for help. "By a norm on R^n we mean a function ||.||:R^n->R for which ||x|| >= 0, ||x|| = 0 iff x = 0, ||x+y|| <= ||x|| + ||y|| and ||ax|| = |a|||x|| for all a in R. Show that any norm d...
by Fafnir43
Fri Jun 20, 2008 2:35 pm UTC
Forum: Mathematics
Topic: Math(s)-Based Anger
Replies: 20
Views: 2411

Re: Math(s)-Based Anger

Bonus points if the mistake is either a copying error or a "two plus two is five!" moment. I have made many of both, and they tend to be remarkably resilient to checking...
by Fafnir43
Thu Jun 12, 2008 5:21 pm UTC
Forum: Mathematics
Topic: Your Axiom of Choice is SILLY
Replies: 60
Views: 8982

Re: Your Axiom of Choice is SILLY

The nice thing about axioms in any system, though, is that they are always true, modulo your formal system. Of course, sometimes, they're both true and false , and those kinds of systems aren't terribly useful, but decades of research hasn't shown any contradictions in ZFC. Better - it's been prove...
by Fafnir43
Thu Jun 12, 2008 5:15 pm UTC
Forum: Mathematics
Topic: What material is covered in a college algebra course?
Replies: 23
Views: 3568

Re: What material is covered in a college algebra course?

Galois theory is definitely covered in most undergraduate Algebra classes. At my college, the third quarter of Abstract Algebra is field theory/Galois theory. I'm uncomfortable with the use of "most" in that sentence, unless you took a survey or something... My experience did not include ...
by Fafnir43
Wed Jun 11, 2008 3:44 pm UTC
Forum: Mathematics
Topic: Analysis Textbooks: Rudin vs. Buck
Replies: 11
Views: 2824

Re: Analysis Textbooks: Rudin vs. Buck

Also, analysis can be one of those courses that's the mathematical equivalent of running headlong into a brick wall, especially if you haven't done much pure maths before. If you don't already have at least a passing knowledge of the important concepts, then I would strongly recommend taking the cou...
by Fafnir43
Mon Jun 09, 2008 12:22 am UTC
Forum: Mathematics
Topic: Theorems named after the wrong people
Replies: 21
Views: 8792

Re: Theorems named after the wrong people

Also, the Cauchy-Schwarz inequality is variously known as the Cauchy inequality, the Schwarz inequality, and the Cauchy-Bunyakovsky-Schwarz inequality. Draw your own conclusions from this. :) Not to mention the Dottie number...
by Fafnir43
Sun Jun 08, 2008 10:07 pm UTC
Forum: Coding
Topic: Bludgeoning Java into making a generic parser
Replies: 10
Views: 1720

Re: Bludgeoning Java into making a generic parser

Yeah, I guess that would work... :oops: No more late-night coding for me! Thanks, guys. Of course, the next frustration is the Netbeans 5.5 GUI builder... Because when I make a jTextField shorter to align with another one nearby, I obviously want it to snap straight back to its original length. Or t...
by Fafnir43
Sat Jun 07, 2008 9:38 pm UTC
Forum: Coding
Topic: Bludgeoning Java into making a generic parser
Replies: 10
Views: 1720

Bludgeoning Java into making a generic parser

OK, so Java has got me just about at the end of my rope. What I'm trying to do should be reasonably simple - define a generic parser class (taking type T, say) that takes a file, splits it into entries, feeds each entry to a parse function belonging to T, and returns a T-vector filled with the resul...
by Fafnir43
Sat Jun 07, 2008 1:22 am UTC
Forum: Mathematics
Topic: Qualified for grad school?
Replies: 4
Views: 1369

Re: Qualified for grad school?

My instinct is you'll be fine. A lot of universities have a first year course with a name like "Intro to Abstract" or "Numbers and Sets". It's designed to sound friendly, then terrify people not suited to high-level math into fleeing for the social sciences now, while there's sti...
by Fafnir43
Fri Jun 06, 2008 12:12 pm UTC
Forum: Gaming
Topic: D&D 4th Edition [and other..oh, who are we kidding. 4th Ed!]
Replies: 777
Views: 62493

Re: D&D 4th Edition [and other..oh, who are we kidding. 4th Ed!]

Aaand it looks like Amazon decided to break street date on preorders, so I've been spending a fun day looking through all the books... :) There are a few irritating things (I don't like the reduced impact of stats on hit points, for example), but overall it looks pretty fun to play. Can't wait for ...
by Fafnir43
Fri Jun 06, 2008 12:09 pm UTC
Forum: Mathematics
Topic: Quiz me on infinite series!
Replies: 16
Views: 2424

Re: Quiz me on infinite series!

Yup - the RIemann hypothesis concerns values of the zeta function with Re(s)<1, at which point that formula becomes meaningless and you have to resort to analytic continuation. 1. Sigma(n = infinity, k = 1): 2 k /5 k By geometric test where |r| = 2/5 < 1, this series is convergent, the sum being 5/3...
by Fafnir43
Thu Jun 05, 2008 10:47 pm UTC
Forum: Gaming
Topic: D&D 4th Edition [and other..oh, who are we kidding. 4th Ed!]
Replies: 777
Views: 62493

Re: D&D 4th Edition [and other..oh, who are we kidding. 4th Ed!]

Aaand it looks like Amazon decided to break street date on preorders, so I've been spending a fun day looking through all the books... :) There are a few irritating things (I don't like the reduced impact of stats on hit points, for example), but overall it looks pretty fun to play. Can't wait for m...
by Fafnir43
Mon Jun 02, 2008 11:42 pm UTC
Forum: Mathematics
Topic: Amusing answers to tests
Replies: 393
Views: 61847

Re: Amusing answers to tests

After that, I wanted to be the one who organizes the thing since I wanted to propose the trisection of an arbitrary angle as a similar problem. (since everyone knows that it can't be done, while, actually, it can) Alas, it was then too late for me. By leaving out or weakening the "with a strai...
by Fafnir43
Mon Jun 02, 2008 6:31 pm UTC
Forum: Mathematics
Topic: Amusing answers to tests
Replies: 393
Views: 61847

Re: Amusing answers to tests

After that, I wanted to be the one who organizes the thing since I wanted to propose the trisection of an arbitrary angle as a similar problem. (since everyone knows that it can't be done, while, actually, it can) Alas, it was then too late for me. By leaving out or weakening the "with a strai...
by Fafnir43
Mon Jun 02, 2008 6:23 pm UTC
Forum: Mathematics
Topic: A most mysterious of numbers
Replies: 33
Views: 5770

Re: A most mysterious of numbers

Hold on... shouldn't we name things after deserving people who do much work on something, rather than any idiot who can pick up a calculator? Fermat's last theorem? That's a special case. Fermat had quite a lot of theorems without published proofs, but from the fact that they all turned out to be t...
by Fafnir43
Fri May 30, 2008 8:59 pm UTC
Forum: Mathematics
Topic: Amusing answers to tests
Replies: 393
Views: 61847

Re: Amusing answers to tests

The phrase "train wreck" has gotten a little play in both my exams so far - first when it took me about half an hour to correctly cube a 3x3 matrix, then when I got about two thirds of the way through a long question only to realise that the final part needed something I had completely for...
by Fafnir43
Thu May 29, 2008 9:12 pm UTC
Forum: Gaming
Topic: D&D 4th Edition [and other..oh, who are we kidding. 4th Ed!]
Replies: 777
Views: 62493

Re: D&D 4th Edition [and other Gen-Con news]

Yes, /tg/ got its mitts on it and leaked it. I'm pretty angry about a good deal of the changes (Mind flayers don't instaeat brains? Disease only lasts an encounter? No ability damage? Any color of dragons can be any alignment? No more metallic dragons? Orcus is only 3 CR levels above the maximum? Y...
by Fafnir43
Tue May 27, 2008 12:05 pm UTC
Forum: Logic Puzzles
Topic: Suicide puzzle
Replies: 10
Views: 3230

Re: Suicide puzzle

It looks as though the base you're using might be changing with each word somehow...
by Fafnir43
Tue May 27, 2008 11:59 am UTC
Forum: Mathematics
Topic: Amusing answers to tests
Replies: 393
Views: 61847

Re: Amusing answers to tests

I prefer "little gnomes", myself. You can probably expect a few silly answers from me in a couple of days - I really wish the exams weren't so close...
by Fafnir43
Fri May 23, 2008 6:50 pm UTC
Forum: News & Articles
Topic: Answers on the back of a music GCSE...
Replies: 9
Views: 1407

Re: Answers on the back of a music GCSE...

I think the real problem is the question it raises - why the hell do we put a vital part of our educational system into the hands of an organisation that can't be bothered to proofread the papers they produce? This was not a difficult error to spot. (To anyone outside the UK: this is not an isolated...

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