« first day (1747 days earlier)      last day (3266 days later) » 

12:04 AM
@Owatch help
$\frac{1}{e}^{-x}=(\frac{1}{e^2})^{x+1}$
The x+1 is an exponent on the fraction
 
@Maximilian The term on the LHS is just e^x
 
Thanks Karl:P
 
@Maximilian $-x\ln{\dfrac{1}{e}}=(x+1)\ln{\dfrac{1}{e^2}}$
 
Thank you, ill need to refresh my memory of logs:P
 
12:26 AM
you don't even need logarithms
this is a problem for the "method of relating bases"
simplify both sides to $e^{\rm something}$ and then use the fact $b^u=b^v\implies u=v$ (for real numbers anyway)
 
@Hushus46 $\int_a^b{\frac{1-2cos2\theta + (cos2\theta)^{2}-sin^{2}\theta - 2cos2\theta*sin^{2}\theta - (cos2\theta)^{2}sin^{2}\theta *d\theta}{4}}$
...
It's bad.
That is the result of substituting $(\frac{1-cos2\theta}{2})$ for $sin^{2}\theta$, then replacing $cos^{2}\theta$ with $1 - sin^{2}\theta$
 
12:55 AM
off topic - Can $|1-a|<1-|a|$ be solved for $a\in \mathbb{C}$ with $|a|<1$? It is my answer to a question, but I am not sure if I can more explicitly describe the $a$'s.
 
@Owatch, do this. $\sin^4t \cos^2 t = \frac14\sin^2(2t)(1-\cos(2t))/2 = -\frac18\sin^2 (2t)\cos (2t) + \frac1{16}(1-\cos (4t)$ now all terms should be integrable.
 
user147690
@TheSubstitute so you mean $|1-z|\lt 1-|z|$? (Which you should draw as circles)
 
@AlexClark i want strict inequality.
I have drawn circles, but I wonder if I can explicitly solve that for $a$.
 
user147690
E.g. can you take $|1-a| +|a| \lt 1$, $|1-a+a|\lt 1$?
 
Say something :)))))
 
1:02 AM
$|1-a| + |a| < 1$ has no solution by triangle inequality.
 
@AlexClark sorry I had the wrong inequality sign. I meant $1-|a| \lt |1-a|$. Can that be solved?
 
user147690
Oh okay, I was confused by that haha
 
thanks for the correction!
 
@TheSubstitute Everything off of the degenerate ellipse $\{a: |a|+|1-a|=1\}$.
That degenerate ellipse is an interval in $\mathbb R$.
 
@KarlKronenfeld thanks!
 
user147690
1:24 AM
@Kaj You enjoy combinatorics?
 
1:45 AM
@Karl Interesting...I've never head of the "degenerate ellipse"
@KarlKronenfeld Interesting, never heard of the "degenerate ellipse"
 
@AlexClark, it's alright sometimes. My favorite subjects, though, are ordered nicely by reputation on my profile
 
Hi @Kaj
 
Hey there @TedShifrin
 
user147690
@TedShifrin Do you know much about tropical geometry?
 
nope.
 
1:48 AM
Morning, @Ted
 
@TedShifrin have a nice semester?
 
sounds pleasant
 
user147690
@KarlKronenfeld Haha yes
 
Goodnight^3, Mike. Well, how'd it go?
 
It appears to have been very well received. Still, pretty stressful.
I substantially reordered it about half an hour beforehand. :P But I think it was a serious improvement.
 
1:49 AM
It'll be a great feather in your cap. Be proud you were asked.
 
@TedShifrin, a square wheel "rolls" on inverted catenaries. Do you know whether inverted catenaries work for any polygonal wheel?
 
Mostly, yes, @jm324354, thanks. You?
What do you think, Kaj?
 
user147690
@KajHansen Do you mean regular-gons?
 
I do think so. Doug and I are discussing it right now @TedShifrin
Yes @AlexClark
 
user147690
@KajHansen I also think yes then
 
1:53 AM
So what changes, @Kaj?
 
So we are considering the case of a triangle right now @TedShifrin. Our thinking should generalize nicely. Basically we are saying that, away from the corners, the triangle and the square are indistinguishable.
 
But it has to roll nicely at corners, too.
Tell Doug I saw his HS teacher last night.
 
just go down the catenary and pick the right half angle.
 
Which means if the wheel is making contact with the curve at a point that isn't the corner, then the two road-curves are locally indistinguishable.
 
Agreed, Kaj.
 
1:56 AM
I'm not sure I agree. The curvature of the road will depend on lots of features of the wheel.
 
But something must change, since as $n \rightarrow \infty$, the road should more and more closely resemble a line.
 
keep working, Kaj.
Did you guys actually work that problem last spring?
 
I didn't, haha
I have not done my due diligence here.
I don't know about Doug.
@TedShifrin, we're now thinking that the number of sides determines where the catenary is getting cut off. For a 100-gon, we are gluing together only small neighborhoods around the catenaries' maxima. For a triangle, however, we include a much larger interval centered at the maxima of the catenaries.
 
Ok. Work out the details :)
Hi @AlexW
 
Interesting problem though. You should include the generalization in your geometry book :D
 
2:05 AM
Hello @Ted. :) How's it going?
 
Fine ... How's your non work going?
 
How do you do a problem with a exponent as a log?
I have $x=3^{log_3(8)}$
How would i start it?
 
Not so bad, @Ted. Lots of long walks. Not as much math as I'd like at the moment, but I'm warming back up to it. It seems I'm a bit more fatigued than I thought, for the time being.
 
Think about what $\log_3(8)$ means.
 
2:07 AM
@Maximilian Simplify the log exponent, or bring it down
First is easiest.
 
3^x=8?
 
You can't bring it down.
 
You can't?
Can't you take the log of x, and 3 to it's power?
 
Oh, if you take logs of everything, ok.
 
Then move log base 3 (8) down in front? I don't think it would work, but I thought you could do that.
 
2:09 AM
No, @Maximilian. Give me a sentence defining that log.
 
3 to the x power equals 8?
 
Where are you walking, @AlexW?
Yes @Maximilian.
so, what's the answer?
 
I don't know:O
 
There's a nice bike path that runs by my house, @Ted, where there's a shoulder where you can walk with little interference. It goes decently far, and the foliage lining the path is very pleasant. It's very peaceful.
 
@TedShifrin It's gone well, I did well in all of my classes. I can't wait to graduate
 
2:12 AM
less than 2
 
Nice, @AlexW. You still in Madison?
 
For just one more week, @Ted. Then it's back to Cleveland, OH for me until August.
 
No, different $x$'s, @Maximilian. Answer my question without saying x.
Ah, cool, Alex.
 
The Cleve? Nice!
 
Max.
What is the base of log?
 
2:16 AM
3 to the 1.89279 equals 8
10?
 
Yes
 
@pjs36: are you from Cleveland? :)
 
What happens if I have $10^{log(1)}$
 
I have no idea
 
@AlexWertheim Just a few miles south, Akron :)
 
2:17 AM
Finish this sentence: $\log_3(8)$ is the number $y$ satisfying ....
 
You get 1.
 
@pjs36: ah, very nice. Did you go to SVSM then?
 
10 raised to the power of the log of its base gives you whatever you are taking the log of in the exponent.
Eh, I'm trying to find a way to explain.
 
so this would be x=3^8 now?
 
Well, not quite.
$10^{log(1)}$ = 1
 
2:19 AM
@Alex Well, I'm actually from a few miles more south, nearish Canton, but basically nowhere. Just Akron for school, and have been living here for the past few years
 
so x=8
 
And usually, the base (not written) is 10.
Yes.
 
oh damn
That explains a lot
I have the answers and looked at the wrong answer, I thought I was trying to get 11.. oops
:(
Ok.. i see that rule
 
@AlexW Fatigue is probably expected. You worked hard for a long time...
 
Oh, I see @pjs36. Cool! I was just curious. I ran cross country in high school, so I crossed paths with a few places in southern Ohio. I've only been to Canton once.
 
2:22 AM
And are gearing up to work harder for longer. :P
 
10, raised to the power that it requires to produce a number, will produce that number? I feel my logic is wrong or bad. But since a logarithm represents the power to which a base must be raised to give you a number, then having the base to the log of that number will yield the power required to get that number in the exponent, which means you will just get whatever you are trying to get in the exponent.
 
Haha, indeed, @MikeM. I did finally get around to typing up some notes this week that have just been sitting for ages...
 
Next up in things I don't want to do right now, is to draw a direction field.
 
Gotcha, @AlexW. Well, it wasn't quite southern Ohio, still NEO (Stark county), just not anywhere in particular :) I take it you're from the greater Cleveland area, then?
 
@pjs36: that's right! If you google me, you can find out exactly where, if you're so inclined. =P
 
2:33 AM
Nice, very nice indeed. Always fun to meet another rust-belter :P
 
Haha, agreed! I was pleasantly surprised by your reaction. Most people hear Cleveland (or Ohio in general) and have less than nice things to say... =P
 
I like the ads for Cleveland
 
Woah, we've got ads? Awesome!
 
LOL I do love those videos...
 
2:37 AM
Funnily enough, @AlexW, I knew some kids from Georgia, and they did indeed have a unique perspective on Ohio
 
Heheh, having spent some time in the south near Georgia, there are some interesting parallels, so I'd be curious what they'd have to say...
I will concede the weather is better down there. :)
 
 
2 hours later…
4:14 AM
The chat is too silent!!
 
user147690
Nah, two people have talked in the last minute
 
user147690
Why did Cleveland's population boom and then shrink? Does that happen in many places in America?
 
user147690
It had 915,000 people in the 1950s and now it has 390,000 people
 
user147690
I meant 'has this happened in many places in America?'
 
user147690
5:23 AM
As far as I know, Chris'ssis has never touched functional analysis and dislikes complex analysis
 
5:39 AM
@AlexClark Hmm, Detroit probably.
 
user147690
2mil to 680k wow
 
7:22 AM
You cant just say that the whole world in front of you is a mockery @Chris'ssis And please dont FORCE PEOPLE TO LISTEN TO WHAT YOU SAY!!!!
BECAUSE YOU MAKE SOME UNBASED FACTS "like i know advanced analysis" But i have never seen you do complex analysis or functional analysis Liar!!
Hi@LeGrandDODOM
 
7:42 AM
This is one of the proofs that I posted here since the last year.
@Rememberme To call liar your family not me stupide one. I know more complex analysis than you'll know in your entire life.
 
Well whats the proof that you wrote the proof?
 
@Rememberme I'm not here to share my work with you, work if you wanna have result.
 
Well we will see Others are not like you @Balarka Never comes and brags in front of you saying that he knows more algebraic topology than you Thats the sign of a person who does maths you are just sitting here to gain attention
 
@Rememberme Yes, I know advanced analysis, A LOT. Is it annoying since it comes from a self-educated?
 
Well you see i can be more cold than you
 
7:45 AM
@Rememberme I just ignore you, that's all.
 
We are all self educated .....
Chris's sis bridge is falling down falling down
falling DOWN
 
@BalarkaSen Have you seen "Foundations of Differentiable Manifolds and Lie Groups" by Warner
 
Hello @Balarka
 
@PaulPlummer Nope.
 
@Rememberme One more thing, I only do math for passion not for other reasons. Well, to tell it truth, I like very much when any of my proofs are liked by @robjohn. It's a sign I'm on the right track. The opinion of a super professional always matters to me.
 
7:53 AM
God knows what might be your passion@Chris'ssis
 
I know you mentioned you were wanting to learn some differential stuff and de Rham cohomology, I am in a sort of similiar boat and I found it and it looks like just what I have been looking for. You should take a look at it @BalarkaSen
(although maybe you already had a plan)
 
Thats shows the difference between you and robjohn He never forces anyone to just do analysis he appreciates every bit of math Not like you @Chris'ssis
 
The book I had in mind was Gullemin-Pollack, @PaulPlummer, but let me see.
 
Hi @BalarkaSen
 
7:56 AM
@Rememberme If robjohn and r9m weren't here you would never see me here. When you don't see them coming here be sure I won't return for gaining attention.
 
I would have been more happier then :p@Chris'ssis
What have you been doing these days @Balarka
in maths
 
It's true I'm very excited and extremely glad for my results. This is the way I am not for gaining attentions.
How not to be when I got results like Ramanujan?
 
You and Ramanujan Ha poles apart @Chris'ssis
 
@Rememberme be sure I always appreciate those that are really good at math -> see robjohn. I never see him crticizing me as you do (not only you).
 
@PaulPlummer: Don't read that.
Read Lee's book or something.
 
8:02 AM
Oh is it not good? @MikeMiller
 
No.
Great reference. Not a great textbook.
 
@Rememberme I don't force anyone to consider any of the sentences I write here. I mean you can consider that I have no question created by me (although there are many thousands I created so far - only a profound passion pushed you in this direction)
 
I will never compare myself with robjohn coz i am not that much knowledgeable as him but i am sure of this much that the way you think (sorry to say) is nonsense
 
@Rememberme Give an example. Are you an authority to say that? Because, you know, if not, what you just said is a real nonsense.
 
@PaulPlummer 'sokay. but I think I will do G-P
 
8:03 AM
Hmm okay, I will probably still take a look at it, but I will check out Lee's book.
@BalarkaSen Sounds good
 
Many of them Contradictry statements , saying that other topics are nothing , Analysis the god etc and etc
Well i am hating this discussion which builds to nothing
 
@Rememberme No, no, no. This is just what you like to believe. It's simple: when talking abut non-mathematical stuff, of course I can say all kind of things because I'm not interested in saying things about personal life, as regards mathematics, all is serious.
 
You just think analysis is it No its not remember that
 
@MikeMiller Introduction to smooth manifolds or Manifolds and differential geometry?
 
@Paulp How much of your blog is complete
 
8:07 AM
(books by Lee
@Rememberme Well the post is up
 
Where?
Link pls
 
@Rememberme mathsalad.com
 
Besides that, I'm not here to be criticized by you. Who are you? Why don't you attend some mathematics instead? You talk far more about non-mathematical subject (like @BalarkaSen) , and not only that you do that, you want to put me into a certain kind of light. This is just a lose of time. You'd better learn something instead.
 
I am learning its you who is stuck to a stuff like a leech @Chris'ssis
I cant say i know more than you
 
The first one. Those are two different authors.
 
8:09 AM
That shows that i am learning
 
Oh okay :)
Thanks
 
On the other hand you say you know everything
and that dosent show you are learning
 
I never read Guillemin and Pollack's differential forms section so I have no idea if it's good.
 
Well, Ted says so...
And so does prof.
 
@Rememberme Of course, I'm preparing to publish more papers in this area, I also prepare a book. Be sure I'll still be here for some time. Well, I think I can do the math I like without reciving permissions from you.
 
8:10 AM
ok
 
I'm busy now, and it's also interesting such discussions appear almost all the time when I'm in the middle of some amazing research. I prefer to do research instead.
 
You dont need permissions from me its just that dont say facts like analysis is the world until you havent learnt everything in maths (which you can never)(well no one can)
 
@Rememberme I never said that. Related to discussion yesterday I said those thiongs to @teadawg1337 because he seemed to me very passionate about analysis. Well, sometimes people get discouraged in front of some topics, I just wanted to help him (but it was a mistake from my side - I admite that).
 
Well everyone can infer what you mean
and where has you research gone... Not doing it?
Judgmental....
Can you make me understand in simple language what is an ordinal number (your post mentions it)@PaulPlummer
 
Just say $\omega = \mathbb N$
 
8:18 AM
So I can't explicitly draw out the whole generalization for the OP. :(
 
@Rememberme an ordinal is an isomorphism class of well-orderings of sets
 
whats an isomorphism class Is it set of isomorphisms from one set to another ?@anon
 
what?
 
I dont know whats an isomorphism class I was just guessing
 
was there supposed to be a period in that message?
 
8:21 AM
period?
 
after the word class.
"What's an isomorphism class? Is it a set of isomorphisms from one set to another?"
i.e. two sentences, not one
 
Oh ya ya
Sorry
 
an equivalent term is isomorphism type
 
For the purposes of the post you can assume $\omega = \mathbb N$, although you can generalize the game to other ordinals. @Rememberme
 
for instance, two groups with different underlying sets can be isomorphic, but they both have the same isomorphism type
 
8:22 AM
Ahhh....
 
e.g. the units mod 3 and the cyclic group of order 2 are different groups in a technical sense, but they are both the same type of group. similarly, two different sets can be well-ordered, but they can have the same type of well-order
 
Ahh oh now i get it
Hi @TobiasKildetoft
 
hi
do you know something about c$^*$ algebras?
$test$
 
@Rememberme Hi. I am on my phone, so I will not be writing much
 
It is really tiring to write on the phone
 
8:31 AM
@r9m I'm almost done with it (I just need to attend some details and done)
5
Q: Generalized Alternating harmonic sum $\sum_{n\geq 1}\frac{\left(1-\frac{1}{2}+\frac{1}{3}-\cdots \pm \frac{1}{n}\right)}{n^p}$

Zaid AlyafeaiIs there a general formula for the following $$\sum_{n\geq 1}\frac{\left(1-\frac{1}{2}+\frac{1}{3}-\cdots \pm \frac{1}{n}\right)}{n^p}\,\, p\geq 1$$ What about some restrictions on $p$ , like integers or anything helpful ?

 
maybe one of you know the multiplier algebra of a c-star-algebra
 
@r9m Of course, then I hope I can also publish a paper with it. :-)
 
@Teddy Sorry, does not ring a bell. But then, I don't know much about the topic.
 
@r9m This is the most powerful energizer, solving such problems and getting the desired results!! :-)
 
How are you liking the post? @Rememberme Are you liking how it is written? Is it too long? explain things too much, too little? etc
 
8:34 AM
Well i am reading it .. @PaulPlummer Nice explaining btw
 
@Tobias oh ok
 
It will take me time since i dont know much stuff about what you wrote I am reading slowly and trying to grasp everything
Sorry for that @PaulPlummer
 
That is fine I wasn't expecting you to be done with it, just figured I would ask before forgetting
 
Well its really nicely explained
1
Q: Linear transformations with equal matrices on different bases

Nescio Let V be a finite dimensional vector space over $\mathbb{F}$ , and let $T,S:V\to V$ be linear transformations and $B,C$ ordered bases for $V$. Assume that $$\left[T\right]_{B}^{B}=\left[S^{2}\right]_{C}^{C}$$ (Where $[T]^B_B$ is the matrix of the linear transformation $T$ with respect to bas...

Any takes on that
 
sure I'll answer
reconsidering that response
 
8:47 AM
@anon What are your ideas on it?
 
I answered
 
Nice answer I feel like giving you 900+@anon
Hi@Ramanewbie
 
9:39 AM
Hello @DanielFischer :)
Are you familiar with the algorithm of FastFourierTransform ?
I want to write a version of FastFourierTransform(fft) for the case that N is a power of 3, in which we seperate the input-vector into three subvectors, solve the problem recursively at them and combine the solutions of the subproblems.
 
@evinda No, I'm not. Wikipedia will be a much greater help there.
 
@DanielFischer A ok... No problem... :) Btw.. How is it going on? How is the weather in Germany? :)
 
@evinda The weather is changing, sun alternating with clouds (and sometimes rain). Too cool for the season, about 10-11 degrees.
 
@DanielFischer Aha.. Here it is very hot...
 
@evinda Let's average it out ;)
 
9:45 AM
@DanielFischer Ok ;) Have you been in Crete?
 
No, the closest to that was Greece.
 
@DanielFischer At which region? In Athens?
 
@evinda Peloponnes. Depending on how well you know the geography there, opposite Prothi, near Kalamata, in the region of Sparta.
And of course a little hiking in the Taygetos.
 
@DanielFischer Nice... I haven't been there but it must be great!!! :)
 
@evinda Yes, it's nice. The Taygetos is a bit too dry for my liking, but for one- or two-day tours, that's not a problem.
 

« first day (1747 days earlier)      last day (3266 days later) »