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00:00
@ParthKohli I was being very facetious
I can see that
I wish I knew number theory
@BalarkaSen Wishing for a downgrade, are we?
hmm, facetiousception
Memes aside, I do wish I knew more concrete/classical mathematics.
if I do get in undergrad thats what i plan to do
you did get in, so have fun, I guess
00:04
there's some shittery about seat allocation
ill have to see how that goes
@PathKohli What do you like about analytic number theory? I really know nothing of that stuff.
@BalarkaSen Me neither. I'm just starting out.
Cool. Any specific interest/stuff you heard and you'd like to understand better that belongs to the realm of analytic NT?
hi a @Balarka. Unsleeping again?
Seems to be so
Well, thanks to your propensities, it seems I've invented a new English word :P
00:09
I spent a few hours trying to find a repeating pattern that finds primes
@BalarkaSen I was reading a thing or two about Dirichlet convolution and Dirichlet generating functions.
@TedShifrin we need to convince mr. oxford to put it in their dictionary
@ParthKohli Ahh
maybe American Heritage is more likely.
And Discrete Fourier Transform is pretty cool. There's a lot of stuff that I think I'm missing out on, and I guess I should pick up on it this semester.
So much intertwining - combinatorics with complex analysis, complex analysis with number theory, and so on.
and hyperbolic geometry intertwines with number theory, topology, diff geometry, Riemann surfaces and complex analysis, ......
00:14
I don't know how the story with DFT goes but I remember enjoying the basic Fourier theory I learnt very much
Ted presents it in one of his multivariable lectures as a orthogonal projection formula which stuck with me
DFT ties into group theory a bit :P
Yeah I read how it works for basically any field, including finite fields.
Very interesting, I have no idea how that works
@Balarka: Since you know more analysis at this point, it's basically just the observation that $\{e^{int}\}$ forms an orthogonal basis for $L^2$.
Right, but the analytic subtlety is to prove that the iterative orthogonal projections converges to the original function, of course
00:22
converges in $L^2$. :)
This is where a lot of analysis got developed, actually ... trying to understand/rigorize this stuff.
@Adeek that's a lot of stuff you covered there in 8 months :p (if youre starting from scratch)
@loch: He's nothing if not ambitious :)
I wouldn't vouch for 100% understanding of everything.
 
2 hours later…
02:06
@Ted oh group theory? Now I'm interested
:P
@Fargle I think you mean this one: en.wikipedia.org/wiki/…
Seems about right.
it's one of those theorems which I find interesting not really because of the statement itself but because it's provable
the fact that its proof uses complex analysis etc. is also quite interesting!
ya
the standard proof does, anyways
(some discussion on the possibility of non-analytic proof here: mathoverflow.net/questions/16735/…)
the impossibility result of Murty sounds interesting
 
2 hours later…
04:26
@AlessandroCodenotti Uhh, I just wrote a bit of javascript and the answer... seems to be e
with higher sampling rates it almost always is around 2.7182
04:39
ok nevermind i think i have a solution
05:10
wow this is interesting
05:22
fuck now im at the beginning again
06:19
@MeowMix you want to get to zero then, not below 1!
But yeah, e is the right answer
Do you have/want a proof?
below 0
also i just found a proof
do i share?
Sure, I've seen this before, no risk of spoilers for me!
so first im going to look at a lot of different probabilities
what is the possibility of getting it done in 1 try? 0 obviously
what about getting it done in 2? well here it depends on the first number you pick, so its a bit more complicated
@MeowMix hint: draw the unit square and the $x+y=1$ line
thats jsut a simple integral $\int_0^1 x dx = 1/2$
yes im trying to think about how to phrase this
i used a geometric approach at first
then for each following try you have an extra condition
06:35
@MeowMix that works too of course, I was suggesting a more intuitive (to me) approach
so for example in 3 tries, if $r_n$ is the nth number you choose, you need $r_1 + r_2 < 1$ but $r_1 + r_2 + r_3 > 1$
so this actually creates a solid which is bounded by those two planes and the planes formed by the $[0,1]$ restriction
ugh i have no idea how to phrase this
but do you know where im going
the restriction $r_1 + ... + r_(n-1) < 1$ you can use some simple calc to see it's $1 / (n-1)!$
at least i think
is that right?
the probability that condition is true
Hmm (n-1)! or n! ?
Ah sorry, the last one is $r_{n-1}$, not $r_n$, you're right
then you have the additional restriction
ugh i have a clear image in my head but i cant translate it into words
:( ill work on it tomorrow when my brain is clear, its late
Sure, but that's the right direction you're going in
07:34
suppose we have a polynnomial map between affine spaces....why I should look at its differential in order to know the dimension of the image? it sounds like rank-nullity theorem, but I'd like to have a clearer idea
 
5 hours later…
12:53
xD heck is the garbo chat
Anybody wanna listen about Tschirnhausen transformations and help me decide which approach seems easier? lol
 
1 hour later…
13:59
Do physical units in physics - things like kilograms, meters, seconds - form a group?
@GFauxPas yes, it's the free abelian group generated by the 7 basic SI units
and you combined "like" and "kilograms" into one word
that is true
and so multiplying them by numbers is a group action?
time and frequency form a pair of inverses for example
interesting
and dimensionless units is the identity
conveniently represented as 1
14:01
cool
what about things like "radians per second"
$\mathbf {1} \cdot \mathbf{seconds}^{-1}$?
$\text{rads}^{-1}$ is a word consists of rad and $s^{-1}$ which is the unit of frequency
but we call radians dimensionless. At least, that's what was taught to me
yeah it is dimensionless thus technically speaking radians per seconds has the same units as frequency (this is why it is called angular frequency)
I see
so multiple physics quantities have th same units, such as work and energy both being joules (J)
14:05
@GFauxPas An inverse second is just a Hertz, the unit of frequency, which makes a lot of sense (rads per second = angular frequency)
I thought "Hertz" was a union of physical pain. Like, if you stub your toe, it Hertz
joke fail
I tried
lol
 
2 hours later…
15:42
lol
16:03
Hi guys! I have a math related question which seems to be too broad for math.se, so I hope chat can be a suitable alternative.. In short, I'm looking for ideas regarding a suitable fitness function(s) for optimization and could really use the insights of somebody with a better understanding of spans, spaces etc. I have already explained it in "my home chatroom" (I don't want to spam this room seeing how I'm a newcomer...)
16:20
hey guys
anyone familiar with GMT in here?
16:33
@Permian i guess it's 16:34?
haha no
@LeakyNun geometric measure theory
17:31
2
Q: How to define *dynamical* dimensions?

SomeoneI'm considering a simple toy model. The spacetime is flat with $d$ space dimensions. Using cartesian coordinates, the spacetime metric is Minkowskian : $$\tag{1} ds^2 = dt^2 - dx_1^2 - dx_2^2 - dx_3^2 - \ldots - dx_d^2. $$ A massless scalar field $\Phi$ is propagating in that spacetime accordin...

For all the manifold people here: A hard but interesting question
See CR Droust's answer for the question itself
Anonymous
18:16
@BalarkaSen Could you come over to hbar if you're around
18:35
screen shot of my assistive diagram chaser app
18:53
0
Q: About the diophantine $ x^2 + t(n) \space y^2 = n $.

mickConsider the diophantine $$ x^2 + t(n) \space y^2 = n $$ Where $x,y> 0$, $ n>1$ and $t(n) > -1$. For a given $n$ we want to find the smallest possible integer $t(n)$. Clearly when $n$ is a square then $t(n) = 0 $. When $ n = a^2 \space b $ then $ t(n)$ is at most $t(b)$. If $ n $ is a prime...

Any ideas ?
 
1 hour later…
20:22
I've got a question concerning a proof verification. Would anyone mind reading through it? math.stackexchange.com/questions/2844790/…
hi @Daminark
20:55
@Daminark, your name sounds like "Damn, a Narc!"
:D
Lmao
No, no, it's Demonark.
21:14
Ted's devices have very strange autocorrect, and this is the result
is this room ded
So it seems. Press F to pay respects
F for Fake news
ich habe ungeschlafen @Ted
21:30
the zero divisors is a union of prime ideals
the non-units is a union of prime ideals
the nilpotents is the intersection of every prime ideals
21:45
maybe we're all just prime ideals
hi @loch
maybe you're the nilpotent one, dork
GOTTEM
@loch so as you might know i'm redoing AM
i think I didn't even finish 1.21(iii) on the first try
Children folklore will be written about the burn that I have just witnessed
My condolences @loch
@loch but here we go
21:49
wow
this chat is not very friendly
oh
@loch is CRing->Set conservative?
what does conservative mean?
lmao
it reflects isomorphisms
21:51
alright, what does reflect isomorphisms mean
a ring hom is an isom iff it is an isom as map of sets?
right
anyway, yes
ok cool
22:02
every minimal prime ideal contains only zero divisors
but not every zero divisor is in a minimal prime ideal!
For example?
k[x,y]/(x^2,xy)
your only minimal prime ideal is (x), but y is a zero-divisor
fake news
think about what this picture looks like - and then you'll learn more about this in ch5 of vakil, or when you read about associated primes in AM (which lacks the picture lol)
22:07
so this is the closed subset {(x,y) | x^2=xy=0} in A^2
so x=0
i mean, rad(x^2,xy) = (x), then just Nullstellensatz
but k[x,y]/(x^2,xy) is not k[x,y]/(x) right
the latter is just k[y]
22:19
indeed set theoretically you only see a line
but the scheme strucutre shows you something more
this is a line with a non-reduced point (embedded point) at the origin
22:33
you can also think of this as intersecting the double line $x^2=0$ (so a line, but fatter), with the usual $xy=0$
so you see that $xy=0$ kils the non-reduced part of $x^2=0$ away from $0$
@anon sry for le memes
memes are acceptable
what up on your end
havent seen you around for a while in chat
nothing really mathematically. writing some lie theory lectures for undergrads next semester. want to make it sufficiently physicsy to attract physics students. otherwise hanging out with friends and doing stupid stuff.
what up in chat?
that sounds pretty dope tbh. i should learn some lie theory at some point of time but haven't had a good reason to other than 'looks pretty dank'
chat has been stable. we made a side-chat for a group of us which is honestly more active lol
22:39
well, mine is going to be baby stuff, plus some of my pet topics (S^3, spin, accidental isos, mobius transformations) at an elementary level.
zero-divisor times anything is zero-divisor
non-zero-divisor times non-zero-divisor is non-zero-divisor
like, matrix groups with no charts/atlas stuff
aha gotcha
hi dogatemy
secretly you can do some geometry with the exponential map, 1-parameter subgroups and the Lie derivative/commutator
22:42
yeah, I considered the proof of the spherical law of cosines with quaternions and 1-parameter subgroups as an exercise.
dunno about commutator
hopf fibration (and its symmetry group Spin(2)xSpin(3) within Spin(4)=Spin(3)xSpin(3)) is part of an optional lecture I'm thinking
I don't think I have seen that proof, that's pretty cool
the symmetry group being the isometry group of the Hopf foliation?
23:10
@MarcGravell Wave from the future
future wave
v a p o r wave
worst genre after nightcore
:(
u don't have a e s t h e t i c c
I am glad.
23:13
@AlessandroCodenotti Future Alessandro told me to send a message to you
@AlessandroCodenotti Future Balarka Sen told me to intercept this message of Future Alessandro and inform you that it is not true.
@anakhronizein Intercept future Alessandro's message and tell him that it's false.
Future @AlessandroCodenotti, your message is false.
I'm confused
23:19
@BalarkaSen An alternate-timeline version of anakhronizein would tell future-present Alessandro that my message would be false, so give future-past @anakhronizein misleading instruction
Ok I'm leaving this madness to sleep! Bye
I'm basically rewriting the script for Primer
Great movie.
23:44
@BalarkaSen just so long as you don't start reenacting it, that'd just be confusing

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