for the undergrads there are low dim topology lectures that have a really good lecturer

Hi

Who's that, @Eric?

ive gone to a lot of the ones for undergrads bc that’s technically the program i’m in and the organizers like got mad at undergrads for going to the grad lectures

Hi Fuzzy

You belong at grad lectures. So sneak in to a few if they're good.

i should’ve applied for the grad program cuz the undergrad program is way too easy

yeah

You should have asked me.

the lecturers name is purcell or something

Let me have a word with them

it was my bad i was a fool

Hmm ...

i think i’ll probably go to the grad ones this week

Jessica Purcell?

yes i think so

I don't know her, but I just looked her up. Now in Australia, but a student at Stanford under Steve Kerckhoff. Very cool.

You should find Rafe there, too, @Eric. He's one of the people in charge.

shes a good lecturer

This attempts to prove that a non-decreasing function has only finitely many numbers $a$ in $[0, 1]$ with $f(x^{+})-f(x^{-}) \gt \epsilon$

@TedShifrin yeah i’ve meant to track him down to say hi

sorry to hijack your conversation, but how do you do that? just wait outside their door and then say "hi im X"?

ive always had trouble talking to people I dont know

But it's is obviously wrong?

It seems pretty right to me.

Except you meant $a$ instead of $x$ in what you typed.

Yes but you keep saying stuff don't stop at hi I'm X

Why do you think it's wrong, @Fuzzy?

thats as far as my imagination goes

The way it writes out the $a_i$'s

Can you actually speak in complete thoughts? Say exactly what you claim is wrong.

@s.harp I try to find something mathematical to ask about

spit truth and truth will spit back

@s.harp well ive already met the person we were talking about so

hi @loch

Hi @TedShifrin

@s.harp You can probably post the question about possible isometry groups of noncompact manifolds on MO

Seems interesting to me

Don't see how to prove it

Could i ask an english question ?

In what language, @parvin?

It's about "ternate" as adjective, I don't know how to use it in a sentence! Can anyone help?

I don't even know the word.

I assume it has something to do with triples or thirds.

I don't understand the first step, if the numbers $1_1, \dots a_n$ are any numbers $a$ with the property discussed, then finding a bound on how many of them there can be proves nothing, and if they're supposed to represent all the possible numbers $a$, then it's wrong to write them in a list?

Why are you packing? @Ted

Hi everyone

Ternate is the largest city in the Indonesian province of North Maluku and an island in the Maluku Islands. It was the capital of the former Sultanate of Ternate and de facto provincial capital of North Maluku before being moved to Sofifi in 2010. It is off the west coast of the larger island of Halmahera

Hi @Mathein

Because I'm moving about 3 miles in less than a week, @Alessandro.

@loch @MatheinBoulomenos does every irreducible scheme has a generic point?

@Leaky yes

Oh I see

for the passerby the question was: does every noncompact manifolds have some metric with noncompact isometry group?

I have three piano pieces I want to play in a row, like concatenation of the three, I don't know how to write its name, like, ternate (3 pieces) of piano?!

why?

@Fuzzy: Assume you have $n$ of them for some integer $n$. You're going to prove that $n$ can't be very big. If you are convinced there are infinitely many, choose any $122$ of them. You'll then show that cannot happen unless $\epsilon$ is very small.

what in ternation?

Doesn't every irreducible component have a generic point?

irreducible = every non-empty open subset is dense. Density is transitive so wlog assume affine. But in the affine case it's clear since irreducible components correspond to minimal primes

I would probably say triad, parvin.

Although in music that means something else, I realize.

Or a triple of pieces.

noncompact means - (the manifold is not bounded or closed?

one idea is to cook up a vector field X for which you can construct a metric with X killing, but you have to work out how to deal with periodic trajectories or non-closed trajectories; you cannot eliminate them completely, or the manifold itself should be a product M' x R

@MatheinBoulomenos so focus on one affine open subset, and pick a generic point there?

and that will be a generic point for the whole scheme?

yes

cool

@Ted do you know Voisin? She gave a talk here this week

Dumb question :P

:P

Voisin?

oh right

Voisin?

lol

I got sniped

I don't know her personally, but she's extremely famous.

I went to a talk she gave in Trento, I understood next to nothing

I imagine she gave an excellent talk.

@Ultradark the topic is the construction of Galois representations associated to modular forms and the necessary background for that (modular forms, algebraic geometry, étale cohomology)

it was quite interesting, the topic was enumerative geometry and Hilbert schemes

@TedShifrin thank you ted

Enumerative geometry is one of my favorite things, @Mathein.

(I understood nothing because I wan't even close to having the required background, not because the talk was bad)

@MatheinBoulomenos what is the essence of enumerative geometry and Hilbert scheme

So if my set were to be infinite, the number of elements I can draw at a time should be arbitrary, but that can't be, especially for big values of epsilon, and that reflects the fact that if the discontinuities are finite, we can only make epsilon very large before none of the $a$'s satisfy the property anymore.

@MatheinBoulomenos how long is this thesis

and what font size (algebraists love small fonts)

@RyanUnger it's going to be pretty long

I think you're making it all very confusing, @Fuzzy, but basically that's correct. I imagine the $\epsilon$ is fixed to start with, however.

I have \documentclass{book} and I have chapters sections, subsections and subsubsections

So default font size is 10pt.

I think UGA required theses to be in 11 or 12 pt type.

Ted, for some reason geometric analysis has decided that standard 12 pt with standard margins is the norm

I have very small margins

In set theory thesis we have $\omega$-subsections, which are contained in all subsubsub...subsections for finitely many subs

I think 11 pt is a reasonable compromise. Sadly, a lot of textbooks (including at least one of my own) get set in 10pt and it's hard to read.

Thanks @TedShifrin.

oh jeeze so many pings while i was away

Those are journal margins (because pages are smaller). It's a waste of good paper to use them for regular purposes.

I just checked out of curiosity and apparently I used 10pt in my bachelor thesis. I had no idea

@MikeMiller ok, I will give it a try

Uh apparently in Bonn there's both a minimum and a maximum length for a thesis, we only had a soft maximum length in Trento

LOL, you're providing detailed background in fractions of pages ...

that's not the whole table of contents though

@TedShifrin I haven't fleshed out the sections yet

Ohhh.

I still have a lot of things on paper and in my head

I was gonna ask how much you were fitting on p.6.

Maybe infinitesimal point size.

@MatheinBoulomenos lmao

@RyanUnger Over a hundred pages for a bachelor thesis? wtf

I have nothing to present for my thesis...

Oh, unrelated but all this talking about theses reminded me of it, I found a great source for Connes's reconstruction theorem if you're interested @Ryan

@AlessandroCodenotti 141 not including bib

it's also like

12 point font

@RyanUnger lol my bachelor thesis was like 20 pages. Here in Bonn we have an hard limit of 100 pages even for the master's

I don't think it's going to be under 100 pages for me with my current plan

my group did write 77 pages for our 3-week year 2 group project on knot theory though

I could not have proved the Yamabe conjecture in fewer pages

There's not a lot of fluff

I cut out some stuff on homotopy groups of LCF manifolds

font size, for reference i.gyazo.com/d6b8833a17b02bedf77d74c3fdafbf7f.png

@AlessandroCodenotti oh cool

preparing my CV makes me want to puke

both because I hate having to be a "salesman" for myself

but also because I feel like it's thin in places

@RyanUnger The full reconstruction theorem is pretty crazy

"One should not be misled by the expression $|\nabla\phi|^2$: it is by no means a positive quantity!"

:S

Sounds like bad notation then

What exactly is it then

It's $g^{\mu\nu}\partial_\mu\phi\partial_\nu\phi$

@AlessandroCodenotti i forgot you were at bonn. the website is very organized

ah, that'd do it

@MikeMiller I am, I'm only a master's student though :P

in my hyperbolic PDE class we wrote that as $|\partial\phi|^2$ to differentiate from the spatial part of the gradient, which is positive

probably not ideal but better than this

So it's like saying $a^2=a_1^2+a_2^2+a_3^2-a_0^2$

(some things on the website are a pain to find, but it's much better than the website of my previous institution)

yeah

that's not great but I can understand why they're stuck with that

yeah, I figured that was just a list of graduate students

i mean, I'm fine with $(\partial_\mu \phi)(\partial^\mu \phi)$

but that gets laborious

Yeah I don't know what the best solution is

Choquet-Bruhat writes $\partial\phi\cdot\partial\phi$

it's stuff like this which makes me respect the intention of penrose notation if not the actual practice of it

looooool

can you even describe inequalities using Penrose notation

sure. write two bunches of squiggles and put > between them :P

(whether you should is another matter)

I mean I guess you can throw an integral over some Penrose notation mess

How do i write the energy momentum tensor in Penrose notation

big brain

Is there a functional equation connecting $\sum_{n=1}^\infty p_n^s$ with $\sum_{n=1}^\infty (-1)^n p_n^s$?

Or $\sum_{n=1}^\infty \frac{p_n}{n^s}$ with $\sum_{n=1}^\infty \frac{(-1)^n p_n}{n^s}$?