Thanks @AkivaWeinberger , I'll save that and study it!

@Semiclassical I don't know if you have a 3ds but Ibe found it a worthy investment

haven't spent money on video games in a long while

Food is more important, @Semiclassic?

Not creating new distractions for myself, I guess

oh, yeah, I know about you and distractions

Anyone know anything about kernels and mind giving me some 2 min advice?

kernels of corn?

I wish! I'm starving!

Oy ... sorry.

Maybe some of the kernels fried chicken would do good

If you've got a question, go ahead and ask it

who knows what you get when you spell it that way :P

@SemiC I don't find that the number of distractions is what matters for me

No, true enough

But spending money on them doesn't seem like a great idea :)

I have an XOR graph: a circle at (-2,1), a square at (2,1), a square at (-2,-1), and a circle at (2,-1) and I'm trying to separate them using a support vector machine (Machine learning stuff). I am trying to write a kernel function that would lead to zero training error using SVM. I asked on cross validated but thought some math dudes would know

oh, crap, that sort of kernel?

I have no clue.

Dr. Shiffrin there's some diff geo in ML!

yeah, dunno

@Mike: That may be, but I have no knowledge about this

haha thanks thought I might as well ask I guess just mapping from (x_1,x_2) --> (x_1*x_2,x_2) could work

@Ted

You still at UGA?

Do I know you, @Mike? ... I retired about 1 1/2 years ago, so no.

I read your class notes a few years back when I was an undergrad taking Diff Geo

Ted > DoCarmo

Oh ... :) LOL, thanks.

If you give me a math question, I might figure it out, but I have no idea what you're talking about there ... :(

haha all good, i've been working through some ML books and came across this problem

Well, get some dinner and good luck !

thanks! Have a nice evening guys

hi @ted

you still here?

hi @adeek

hey @TedShifrin just the galois group can be thought as a subgroup of $s_n$ where n is the degree of the extension ?

just verufying

hey @KasmirKhaan

verifying *

how to parametrize abs(z-a) =r

z is complex

@adeek ted is afk :( wanted him to help me too

I am sorry @KasmirKhaan I am very busy atm

its ok mate :)

@Adeek Think about this for a second

A Galois group is a finite group of order $n$, where $n$ is the degree of the extension

What do you know about every finite group of $n$ elements

@Mike I would love it if you added an extra letter to your name :)

yeah I agree it is @Krijn

anyone can help me ? :)

Maybe think less C and more R^2.

for instance, abs(z-w) is the distance between points z and w. so what curve does abs(z-a)=r represent?

a circl

right.

what bothers me is the point a

eh, it shouldn't. if it does, take the case a=0 and worry about it later.

i know that e^it represent a circle of radius 1 centred at orgiin

sure. how would you shift that circle?

in that case re^it

circle of radius r

centred at origin

right

how could I shift all the points in the circle to the right by 1?

i subtract 1

eh, you'd do plus 1

e.g. 1+re^it

(x-1) ^2

shifting circle to right

that what i meant

the equation of a circle, sure

but not the parametrization of one

oh so you mean a+re^it ?

Well, let's see if that works.

What's abs(z-a) if that's z?

it shoudl work

:D

Ya

hmm if r =0 we are at a

and we can go maximum distance r from a

thanks @Semiclassical

np

what do you study semi ?

Physics

nice

am in second year mathematics

and i still not getting how to study

undergrad?

yes

I can't give good advice for studying, alas

@MikeMiller What letter?

its ok , i will find my paste with time i hope :D

@Kasmir sometimes u need to stop spending days trying to mentally picture a theorem or lemma and just accept it and move forward if u are having trouble

@mike its a good advice thanks , that what happned to me in first year , i spend weeks on one subject and didint get good grades

i wanted to be perfect at everything so i missed alot

Your favorite! Preferably not M.

(I get pinged for messages to you)

oh we have 2 mike :D

by rules of comedy you guys should be friends

three, in fact, though not by name here

:D

my real name is not kasmir khaan either i dont know why i picked this name tho lol

I picked this name because a lot of the research i've done has been in the realm of semiclassical computations. (don't ask me to get into that, though)

then i wont :)

but ill have to google that now since you mention it

Lazy problems on the main site never cease to irk me: math.stackexchange.com/questions/2054871/…

what if it is a guy actually brewing coffee?

what if he made that diagram?

Then the world is a far stranger place than I'm willing to accept.

what do you quantify as "lazy". I can write questions with no context

but yet are complex enough questions that they need not have attempts to solve them

because people that can solve them are few and far in between or require very obscure methods.

shrugs

but yeah, that question seems to be a homework copy

True enough. Related rates problems in calculus, however, generally don't fall in that category

hi

It's a judgment call, to be sure. But if it's complex enough that there aren't a lot of people that can answer it, then it's also probably not as easily presented as a textbook problem would be.

(as that problem clearly is)

@Semiclassical that's wrong though. All questions should include their attempts. If someone ends up writing the Riemann Hypothesis by coincidence, they still need to write their attempts. Otherwise, it is obviously too advanced for them and they have no business asking that question.

True.

I think the word 'attempt' is important there. It should be clear what effort you've put into the problem.

Of course, what form those attempts take depends on the problem

in fact, if one is not currently capable of answering their own question given enough time and are not merely stuck on the problem, then they probably will not understand the answers given and shouldn't ask the question to begin with.

For a problem like that, I'd expect to see them talking about the volume of the fluid and wanting to take time derivatives.

And looking for a relation between the volume of the cone and its height, etc.

"Of course, what form those attempts take depends on the problem" They should be a meaningful and useful attempt to solve the problem. It should be a possible solution given minor effort. The question should be 75% answered when the person asks it. If they cannot answer 75% of their own question and solve it with a 3-4 sentence hint, then they clearly do not understand the subject and should have their question removed until it is time for them to lean that subject.

People need to stop asking about subjects that they are not yet studying in their schooling.

This website is not for teaching new material to people.

@Semiclassical I'm sure most people will agree with me on this. It's annoying how people ask questions they are not supposed to be asking yet.

Eh. I don't see that as the biggest issue on the site. I more get tired of people posting homework problems that they're supposed to solve themselves and getting wholesale answers in response.

that may be true

They should be asking questions about their calculus homework. But they shouldn't be posting them here expecting to get solutions.

true

but they should not be asking questions about differential equations or real analysis under any circumstances

it is not time for them to learn that material

and all it will do is end up confusing them and the rest of the website

Probably not, no. But again, I don't see so much of that.

@TheGreatDuck When is it time for someone to ask a question or learn material?

That said, if they notice something weird in what they've been taught and ask a thoughtful, well-stated question about it, then giving the connection to higher-level material isn't necessarily a bad thing.

@fluffy_muffin this site is not for teaching. It is for asking help in solving a problem they have already learned about and are having computational difficulties. They should only ask a question about things they have formally learned about or are experiencing a legitimate real life situation where they need that math.

Don't try to teach that high-level material, of course, but do point out that what they've noticed is worth thinking about eventually.

@TheGreatDuck have you changed your mind?

@Semiclassical true, but it should be closed as lacking context as they are not capable of providing context.

@meow-mix what do you mean?

i think the objective is to learn , you are not helping him passing the test , just helping him with an exercice

Eh, the stuff that they've noticed as being weird could serve as context given a proper statement

I posted many questions here with no try , but after seen the solution i solved the rest of problem set alone

@TheGreatDuck i thought you said you were leaving the site

@Semiclassical they are incapable of attempting to solve the problem and provide a clear proof as to what the answer is. Therefore, they should not ask the question. It is above their level.

@meow-mix no. I said the mods would probably ban me for being overly delinquent. However, they apparently refuse to.

so im still here

I think that's too austere a criterion, but we're speaking in generalities.

@TheGreatDuck So... you've never been able to not answer a question... and never needed help and as such you should never ask a question about it since it's above your level?

Without specific examples, it's a bit silly.

@fluffy_muffin not on this website.

@Semiclassical a person taking high school geometry should not be allowed to ask questions on this site regarding non-Euclidean geometry. They cannot provide a "useful attempt that can be extended with little work to answer the question" therefore, they have failed to produce context.

Context is a partial answer that is actually useful and successful in ultimately answering the question.

if it is not a successful attempt then it is not context.

imo

Eh. Not a useful attempt, sure.

but the attempt should be ultimately successful

it should be of a form where the person can do x number of steps (almost all of them)

and then gets minorly stuck on the last 2 or 3 steps

I think I'd be a bit more tolerant than that, but yeah.

if the attempt was completely useless then they fail to understand the material and are not ready to understand the answer and need to go back and learn more and study more before asking.

There should be at least some foundation to work with.

However one defines that.

@TheGreatDuck im taking high school geometry...

If a person tries to integrate sin(x) via integration by parts then they have failed to understand the concept of integration and cannot provide successful and useful context. Therefore, we cannot help them.

and i frequently ask Ted about non euclidean geometries :P

You ask here, though.

That's different than asking on the main site.

@meow-mix in chat or in a question post, because from my understanding the latter is inappropriate.

@Semiclassical so am i barred from asking questions simply because of my age?

no

on the site, that is

it is because you have not yet studied enough about them to understand how to answer your own question

...?

have i not?

I think my criterion is not as severe as TGD's

lets say you ask how to find the area of some figure on a sphere

if you cannot actually find the area of surfaces on spheres, then you are incapable of providing successful context.

the context should be a proof going in the proper direction

well thats understandable but what you said

if the attempt is completely flawed and using wrong thinking then it is not context, period.

i know

it's weird thinking

:p

is that i shouldnt be allowed to ask questions, even if i have the proper tools to solve it, because of what class im taking

well yes

maybe you should have phrased as you just did instead

ehhh, I think that goes too far.

if you haven't taken a class yet on all the material leading up to it then you are not fully prepared

What matters is the expertise/context they're able to demonstrate.

your context is not suitable for that question

but ive studied it :P

and thats the catch

Especially because, well, at a certain point you stop taking classes on everything you learn.

but you haven't studied everything in between

did you learn calculus?

pre-calculus?

yes

linear-algebra?

and yes

ye

O.O

I've never taken a course on algebraic topology, for instance, but I learned enough of it by myself in order to actually use it in a research context.

i havent studied much rigorous calculus though;

then you are an outlier

Rigorous meaning real analysis?

you break the method

Epsilon-delta

XD

yes, @Semiclassical

Right.

@arctictern are you around ?

This is why I don't like speaking in generalities, though.

ive studied a bit of complex analysis for fun

just want to do some checking with you for something

I'm saying that someone in geometry shouldn't just be allowed to get curious and ask "what does it mean to draw a triangle on the surface of a sphere."

I have few complex analysis recommendations @meow-mix

that question is too advanced for them

residue theorem and laurent series expansions, analyticity, etc etc

how old are you, kid?

I want to study complex analysis and several one more deeply over next summer.

@Adeek well i havent studied that much analysis :P

plus Ted will yell at me for not doing my exercises

:)

@meow-mix are you even over 18?

I don't like the notion of disallowing curiosity. But let's be clear: There's a big difference between spherical trigonometry and Riemannian geometry.

no

(not that that is an issue)

I think the basics of spherical triangles are simple enough that a high-school geometry background is enough, frankly.

Wow, kid. Keep up your studying. There's no way around it. You're a bonified math genius.

:(

For instance, showing that the angle defect is proportional to the area of a spherical triangle? That doesn't need calculus.

im not a genius because of my age, neither should someone be less appreciated for their achievements because theyre older

All it needs is three great circles and a careful thinking through of it.

@Semiclassical but one has not learned three dimensions yet or the calculus of 3-dimesnions. Therefore, they are not really prepared in an anylitic sense.

Eh, pretty sure you see some analytic geometry in high school.

@Semiclassical do you know some galois theory ?

@meow-mix that may be true, but what I mean is that I am over 3 years older then you and you know way more then me. So, continuing based on that trend... you'll probably understand way more than most people ever will.

I want to verify something if it correct or not

I know that there is such a thing as Galois theory :P

which is to say, basically no.

@TheGreatDuck 21?

age shouldn't be a factor, yes, but studying advanced math way past high school math is... certainly not an easy feat.

oh oke @Semiclassical :P

i know some generalities of Galois theory---field extensions, etc.

@Adeek i know that galois was a badass dude, thats for sure

it's way easier to go the long way in classes

@meow-mix yes

@TheGreatDuck oh, ok

btw im not in high school

@meow-mix I want to calculate the degree of the extension $\mathbb{Q}( (2)^{1/8}, \sqrt{2},i)$ over $\mathbb{Q}((2)^{1/8}$

Really, all one needs to understand the area of a spherical triangle (besides knowing the surface area of a sphere) is this picture: goo.gl/images/f1pbHZ

I don't know what the degree of an extension is, sooooo no help there

@meow-mix you're taking geometry...? elementary school then?

well we call it middle school :P

Are you in the American school system, @meow-mix?

@Semiclassical yes

btw, i know it's a subject flaunted everywhere but at your age, you should probably consider the riemann hypothesis. At the very least, it's a subject inter-connecting many concepts.

okay, just wanted to check for context.

6th to 8th grade is what we consider middle school

@meow-mix Same as it was for me.

@Semiclassical just clarifying, i know a few places where middle school is 5th to 8th

and considering your elevated level of knowledge, you might actually have a half-decent shot at it

One point to make, though, is that it matters not just what your own ability is, but the ability of the people you talk with and learn from

Not a lot of middle school math students get to talk to a prof on the level of Ted :)

true

@Semiclassical believe me, a lot of math teachers dont specialize in what they teach in

Oh, I believe you

they specialize in exactly that; teaching

^^^

That's my point, though. If more students were exposed to people who really know and appreciate the math, I wonder how they'd respond?

At the K12 level, I mean. College math is a different beast.

i know that ted tutors kids now; lucky kids :P

@meow-mix Speaking of Riemann hypothesis

The book Prime Obsession is a great accessible resource on that

Yeah, solid book

and apparently there's a free pdf available? linkety link

I mean, it's probably better to actually buy the book

I've got that book, so yeah

Solid purchase

Me too

With a melting point of over 3000 degrees C, it better be

(I need to be asleep. Except I also need to be finishing my assignment...)