## Search found 143 matches

- Wed Nov 12, 2014 5:32 am UTC
- Forum: Mathematics
- Topic: What is the future of Mathematic and mathematicians?
- Replies:
**10** - Views:
**4374**

### Re: What is the future of Mathematic and mathematicians?

So you tell your super advanced theorem program to prove/disprove Fermat's theorem, what does it do? Or even if it tells us yes or no, can we get anything useful out of its proof, or is it purely technical? Unless the computers we're talking about are just replicas of brains I don't think mathematic...

- Sat Aug 30, 2014 1:22 pm UTC
- Forum: Mathematics
- Topic: Is it possible for a math obsession to be unhealthy
- Replies:
**54** - Views:
**14091**

### Re: Is it possible for a math obsession to be unhealthy

As long as you're physically and mentally healthy, and aren't neglecting your responsibilities, you're fine. Nobody is a perfect well rounded human being at 17.

Amad27's comments made me think of Perelman even before someone brought him up. Wait, is Perelman in our midst!?

Amad27's comments made me think of Perelman even before someone brought him up. Wait, is Perelman in our midst!?

- Tue Sep 24, 2013 4:12 am UTC
- Forum: Mathematics
- Topic: Geometry: A line is defined?
- Replies:
**16** - Views:
**3273**

### Re: Geometry: A line is defined?

The idea is geometry can be proven from these axioms. The axioms are chosen so that they describe what we think of as lines and points. But to a computer for example it's all just logical manipulations. Euclid had his axioms (5 I think) but they aren't satisfying to modern mathematicians and someone...

- Tue Apr 23, 2013 3:25 pm UTC
- Forum: Mathematics
- Topic: PDE trace map
- Replies:
**0** - Views:
**1323**

### PDE trace map

In PDE the map that extends "restriction of a continuous function to the boundary" is called the trace map. There must be a reason why the word trace is used, but my google searches have given me nothing. Is there a connection between this map and what we usually think of with the word tra...

- Fri Mar 22, 2013 2:52 am UTC
- Forum: General
- Topic: Ph.D. prejudice?
- Replies:
**22** - Views:
**7135**

### Re: Ph.D. prejudice?

My cousin does this. Probably just insecurity.

- Tue Mar 12, 2013 8:23 pm UTC
- Forum: General
- Topic: Randall: Get a grip
- Replies:
**108** - Views:
**15999**

### Re: Randall: Get a grip

EDIT: And if the OP was talking about men as opposed to boys, why not use "adult", which expresses that sentiment better. I guess my whole thought process revolves around the intent of the speaker. So if we're talking about whether the phrase itself is sexist, we're talking about two diff...

- Tue Mar 12, 2013 12:26 am UTC
- Forum: General
- Topic: Randall: Get a grip
- Replies:
**108** - Views:
**15999**

### Re: Randall: Get a grip

Well, no. Because in ... uh.. pretty much ever context, the meaning of "Man up" is "Stop being such a woman" No, really, it is. Because if the speaker wasn't trying to say "Stop being such a woman", they speaker would say "Grow up" When I hear "man up&qu...

- Wed Feb 13, 2013 2:21 am UTC
- Forum: Mathematics
- Topic: Factorization and geometry
- Replies:
**10** - Views:
**2773**

### Re: Factorization and geometry

Care to elaborate? Or work out an example if you're not sure how to explain it?

- Mon Feb 11, 2013 8:15 am UTC
- Forum: Mathematics
- Topic: Mega millions 5 number prediction
- Replies:
**34** - Views:
**6969**

### Re: Mega millions 5 number prediction

As I understand it the program goes something like this: for a=1 to 50 for b=1 to 50 ... for e=1 to 50{ if a,b,c,d,e do not satisfy any of a large number of completely irrelevant mathematical relationships print a,b,c,d,e } Skiingbandit - as a math forum I think we feel obligated to point out incorr...

- Fri Feb 08, 2013 7:43 pm UTC
- Forum: Mathematics
- Topic: Mathematics - a new basis
- Replies:
**36** - Views:
**7234**

### Re: Mathematics - a new basis

anyone with a solution of triangles, given a solution (not empty talk) about it, I will not argue that. I have a solution to your problem. 1?1 links the correspondence of triangles. Evidence: A, B natural points. There is a line. However, 3?1%2 (where % is derived above) presents a solution of the ...

- Sun Feb 03, 2013 1:11 am UTC
- Forum: Mathematics
- Topic: Application of Krein-Milman's theorem
- Replies:
**4** - Views:
**2216**

### Re: Application of Krein-Milman's theorem

From what I found through a quick google search, Krein-Milman's theorem makes no mention of a norm. Wikipedia: "Let X be a locally convex topological vector space (assumed to be Hausdorff), and let K be a compact convex subset of X. Then, the theorem states that K is the closed convex hull of i...

- Sun Nov 04, 2012 3:17 am UTC
- Forum: Mathematics
- Topic: Finding the derivative of a matrix equation
- Replies:
**4** - Views:
**1551**

### Re: Finding the derivative of a matrix equation

You gave an example of f(X) as X^2, which would return a nxn matrix though? f(X) itself is nxn, f(X) applied to a vector is nx1.

- Sat Nov 03, 2012 8:53 pm UTC
- Forum: Mathematics
- Topic: Finding the derivative of a matrix equation
- Replies:
**4** - Views:
**1551**

### Re: Finding the derivative of a matrix equation

Let A=[a_lm] be the matrix Xf(X). Then Tg(Xf(X)) is a vector valued function, from R^(n^2) to R^n taking X=[x_lm] to [Σg(a_1m),...,Σg(a_nm)] where sums are from m=1 to n. Then the derivative with respect to x_ij is the vector [Σ(g'(a_lm)*da_lm/dx_ij)] ( l=1 to n ). Where a_lm = Σx_lk*y_km (k=1 to n)...

- Mon Oct 29, 2012 4:05 am UTC
- Forum: Mathematics
- Topic: Help with Miller-Rabin Primality test?
- Replies:
**5** - Views:
**1223**

### Re: Help with Miller-Rabin Primality test?

Since you're doing x ← x^2 mod n, x is different each time you go through the loop. You're right that the index in the loop isn't used explicitly. The result in the innermost loop corresponds to seeing whether x^(2^r *d) = -1 or 1 mod n (or neither).

- Mon Oct 29, 2012 1:26 am UTC
- Forum: Mathematics
- Topic: Help with Miller-Rabin Primality test?
- Replies:
**5** - Views:
**1223**

### Re: Help with Miller-Rabin Primality test?

For your first question, I think you go until you get -1 or 1 mod the prime number. In this case a^(2^1*d) gave you -1 so they stopped. Then they tested something else to see whether "221 is prime, or 174 is a strong liar for 221". So you start with 2^0 *d, then 2^1 *d, 2^2 *d, et...

- Tue Oct 23, 2012 6:10 am UTC
- Forum: Mathematics
- Topic: Defining a function regarding my potential class grade
- Replies:
**9** - Views:
**1652**

### Re: Defining a function regarding my potential class grade

If it's not a theorem of algebra then what's it a theorem of. From an elementary viewpoint, it's a theorem about multiplying and adding things in a certain way and getting zero. Seems pretty algebraic to me.

- Sun Jun 17, 2012 7:01 am UTC
- Forum: School
- Topic: Student Trolling
- Replies:
**39** - Views:
**8396**

### Re: Student Trolling

You're an asshole. You have no fucking CLUE about anything in this student's life, in or out of school, and you're just making it the fuck up to justify being an asshole. Stop being an asshole, asshole. You ASSHOLE. I feel like you're being an asshole by calling this guy an asshole. It is a good po...

- Tue Jun 05, 2012 8:22 am UTC
- Forum: General
- Topic: Childhood misconceptions
- Replies:
**868** - Views:
**105690**

### Re: Childhood misconceptions

I also had a traffic light misconception. In school we apparently learned what the lights meant one day, but I must have not been paying attention. I remember thinking for several years that red=stop, yellow=stop, even if you're late, green=go. Makes absolutely no sense.

- Mon Jun 04, 2012 8:18 am UTC
- Forum: Language/Linguistics
- Topic: Words you choose to mispronounce
- Replies:
**242** - Views:
**91306**

### Re: Words you choose to mispronounce

I pronounce water like wooder. I'm always conscious of it whenever I say the word away from home. I always have a quick dilemma, do I try to pronounce it the way most Americans do and possibly butcher it, or do I just say it like I always have and risk being misunderstood.

- Thu May 31, 2012 4:43 pm UTC
- Forum: Science
- Topic: good physics texts?
- Replies:
**9** - Views:
**3803**

### Re: good physics texts?

Why, in your opinion, are these things bad/ridiculous? As eSOANEM explained, Newton's laws really are almost the fundamental axioms of mechanics, at least as it was formulated in 17th and 18th centuries. This is probably getting to the heart of my frustration with physics. I can never tell whether ...

- Wed May 30, 2012 10:52 pm UTC
- Forum: Science
- Topic: good physics texts?
- Replies:
**9** - Views:
**3803**

### Re: good physics texts?

Oh yeah, I'm in grad school for math so that's all fine. I was considering Penrose's book but didn't know enough about it. I'm convinced now though.

- Wed May 30, 2012 7:47 pm UTC
- Forum: Science
- Topic: good physics texts?
- Replies:
**9** - Views:
**3803**

### good physics texts?

So I want to learn some physics as I've recently realized how interdependent math and physics have been as far as development of the theory. I'm starting from scratch, so I accept that there will be mundane calculations to skim through. I looked through the notes for Spivak's Mechanics for mathemati...

- Sun May 27, 2012 5:22 am UTC
- Forum: Mathematics
- Topic: "Oh no! We forgot how to say... math... stuff!"
- Replies:
**294** - Views:
**91726**

### Re: "Oh no! We forgot how to say... math... stuff!"

Sorry to necro this thread, but... I have to get this out of my chest. Index notation is reversed! It should be columns X rows (a row vector should be a n x 1 matrix) in order to obey cartesian coordinates. +1 This would have prevented so much brain pain when learning linear algebra. Whenever I see...

- Sat May 26, 2012 8:28 pm UTC
- Forum: Mathematics
- Topic: After calculus
- Replies:
**20** - Views:
**4683**

### Re: After calculus

eSOANEM wrote:even though I know it's the right process and can understand why it works, integrating up to a variable limit always feels a bit like cheating.

Fubini FTW.

- Fri May 25, 2012 6:19 pm UTC
- Forum: Mathematics
- Topic: Mathematics and Difficulty
- Replies:
**5** - Views:
**1565**

### Re: Mathematics and Difficulty

You're being a little vague about these "problems". If the problem has an algorithm your program could compute or estimate the number of steps ahead of time and use that as a measure of difficulty, but in reality adding two really big numbers isn't any harder than adding two small numbers,...

- Fri Apr 13, 2012 4:35 am UTC
- Forum: Individual XKCD Comic Threads
- Topic: 1042: "Never"
- Replies:
**82** - Views:
**32346**

### Re: #1042: "Never"

This seems like a copy of a previous xkcd comic. Same punchline. I don't quite feel like searching through 1000 of them though.

- Sun Apr 08, 2012 10:18 am UTC
- Forum: Mathematics
- Topic: Analysis - limits and integrals
- Replies:
**8** - Views:
**2148**

### Re: Analysis - limits and integrals

>_< Forgot to mention, there are no poles on the positive real axis.

- Sun Apr 08, 2012 3:55 am UTC
- Forum: Mathematics
- Topic: Analysis - limits and integrals
- Replies:
**8** - Views:
**2148**

### Re: Analysis - limits and integrals

I was thinking about issues like \lim_{n\rightarrow\infty m\rightarrow\infty} \dfrac{m}{n} . It looks like I should have given more context for the problem. It's part of calculating a real integral using the residue theorem. We know a certain integral will equal 2pi*i times the residues, then we sho...

- Wed Apr 04, 2012 1:16 am UTC
- Forum: Mathematics
- Topic: Analysis - limits and integrals
- Replies:
**8** - Views:
**2148**

### Analysis - limits and integrals

This is stuff I should know but am too intimidated to ask the professor. In Bak/Newman's Complex Analysis, pg 148, it says \lim_{\epsilon\rightarrow 0, M\rightarrow\infty}\int_{C} R(z)\log z dz=\int_0^\infty R(x)\log x dx , where C is the horizontal line segment from i\epsilon to \sq...

- Sat Mar 31, 2012 6:38 am UTC
- Forum: Mathematics
- Topic: Motivation for self-study
- Replies:
**3** - Views:
**1402**

### Re: Motivation for self-study

I'm not really concerned too much about forgetting things. If it's a concept I have to use a lot at the time, it will be engrained in my memory, and if not, once I need it I can just look it up and I'll understand it relatively quickly again. And every time you look it up again you'll remember it be...

- Fri Mar 23, 2012 2:02 am UTC
- Forum: Mathematics
- Topic: A metric for mathematicians
- Replies:
**9** - Views:
**2556**

### Re: A metric for mathematicians

dammit. I was afraid that I posted something wrong and my edited message explaining that used a word incorrectly. I can't win.

- Tue Mar 20, 2012 5:07 am UTC
- Forum: General
- Topic: Sleep-time holodeck experiences
- Replies:
**3404** - Views:
**762836**

### Re: What were your dreams last night?

Last night I had a dream where I was frustrated and kind of freaking out that I couldn't see and play my video games with my eyes closed. Normally it works, apparently.

- Mon Feb 27, 2012 12:36 am UTC
- Forum: School
- Topic: Going to High School, need help finding a passion....
- Replies:
**20** - Views:
**6696**

### Re: Going to High School, need help finding a passion....

No, programming is great, but I honestly don't think that it is the healthiest choice of a hobby; after sitting down for 3-4 hours at a time I feel worse than if I was outside playing sports for the same amount of time. --------------- Thanks for all the advice everyone, I really appreciate it! Yea...

- Sun Feb 19, 2012 10:12 am UTC
- Forum: General
- Topic: Sleep-time holodeck experiences
- Replies:
**3404** - Views:
**762836**

### Re: What were your dreams last night?

This dream was actually a few weeks ago. This girl I used to sort of know wanted to have sex in a public bathroom. This bathroom seems similar to the labyrinthine one in one of my two "dream world" schools. She had a condom and I was relieved because I didn't have one. But it was very larg...

- Tue Jan 10, 2012 1:36 pm UTC
- Forum: Mathematics
- Topic: "Therefore" versus "implies"
- Replies:
**12** - Views:
**4099**

### Re: "Therefore" versus "implies"

In the context that you presented the two words, mathematically, mean the same thing. The distinction between your choice of words is the subtle one of our organic language. Certain words seem to me to fit better, maybe because I subconsciously associate different words with different kinds of reaso...

- Wed Jan 04, 2012 11:23 pm UTC
- Forum: Mathematics
- Topic: What's the point of rationalizing?
- Replies:
**61** - Views:
**9163**

### Re: What's the point of rationalizing?

There are lots of ways to write the same thing, so it makes sense to have a standard way to write them. Some students might not recognize that e^{x\ln 2} is simply 2^x . Everyone knows sqrt 2 is about 1.4, so 3*sqrt2 can be seen to be 4.2 easily, sqrt18 isnt as quick to calculate. Same with 1/sqrt(2...

- Mon Dec 12, 2011 12:36 am UTC
- Forum: Mathematics
- Topic: motivation of abstract math
- Replies:
**14** - Views:
**2765**

### Re: motivation of abstract math

Lp spaces end up topologically collapsing, but that is the path down which you form a foundation for Fourier Analysis -- if you have ever seen a noise filter (visual or auditory), or seen an image zoomed, or blurred, or sharpened, or used a camera that electronically de-blurs the image you take, th...

- Sat Dec 10, 2011 10:38 pm UTC
- Forum: Mathematics
- Topic: motivation of abstract math
- Replies:
**14** - Views:
**2765**

### Re: motivation of abstract math

Step 1: Ask a question about why analysis and topology seems so abstract to me. Step 2: Get answers pointing out concrete connections to a bunch of analysis and topology, including most of the things you decry as being hopelessly abstract. Step 3: Give up, and say that they are just abstract puzzle...

- Sat Dec 10, 2011 8:44 am UTC
- Forum: Mathematics
- Topic: motivation of abstract math
- Replies:
**14** - Views:
**2765**

### Re: motivation of abstract math

As far as this affects me, I've realized that it doesn't really matter and it can all be fun in a puzzley way, even if I don't really know what I'm talking about.

- Fri Dec 09, 2011 4:46 am UTC
- Forum: Mathematics
- Topic: motivation of abstract math
- Replies:
**14** - Views:
**2765**

### motivation of abstract math

In my first year of grad school, I feel like I'm learning about shittons of random abstract generalizations and special cases.. to the point where things seem less interesting in their own right. Things in algebra seem to be more natural. You have a handful of central objects - groups, rings, etc, a...