ℝolliℵg M∀th Thr∑a∂

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Yeah

The Glam Of That All The Way From Memphis Man! (James Redd and the Blecchs), Sunday, 15 December 2013 05:23 (ten years ago) link

it would be an interesting history of math to classify what programmes have led to the most research -- i suspect classification programmes themselves would probably lead the pack.

lollercoaster of rove (s.clover), Sunday, 15 December 2013 05:24 (ten years ago) link

classification of surfaces seemed like it didn't take very long once they figured out what they were doing

flopson, Sunday, 15 December 2013 05:32 (ten years ago) link

oh yeah, finite simple groups, too

flopson, Sunday, 15 December 2013 05:33 (ten years ago) link

arguably, figuring out what you're doing is typically the hard part.

lollercoaster of rove (s.clover), Sunday, 15 December 2013 05:38 (ten years ago) link

great little history of the classification of surfaces on appendix D of this book http://download.springer.com/static/pdf/997/bbm%253A978-3-642-34364-3%252F1.pdf?auth66=1387259121_9a9118105634f100257c6f624c9329f0&ext=.pdf (full pdf)

flopson, Sunday, 15 December 2013 05:49 (ten years ago) link

gah i should be studying for my analysis exam... blegh

flopson, Sunday, 15 December 2013 06:03 (ten years ago) link

which 2 should i take next semester out of these 4

real analysis 4 (measure theory, functional analysis)
differential geometry
topics in geometry & topology course on cube c0mplexes
discrete mathematics of paul erdos (taught by the great vasec chv4tal http://users.encs.concordia.ca/~chvatal/6621/)

flopson, Wednesday, 18 December 2013 18:52 (ten years ago) link

real and discrete OR differential and cube complexes

the late great, Wednesday, 18 December 2013 18:53 (ten years ago) link

i sort of hated analysis 3 but while studying for it and memorizing all those theorems i became really impressed with it and now have the urge to take the 4th. also i've heard measure theory is one of those things you've just *got* to learn and this guy would teach it properly

flopson, Wednesday, 18 December 2013 18:53 (ten years ago) link

interesting, why those 2 diff pairings?

flopson, Wednesday, 18 December 2013 18:53 (ten years ago) link

(xp)

flopson, Wednesday, 18 December 2013 18:56 (ten years ago) link

i've always had better luck in school when i take courses with some connection to each other rather than courses which have different approaches

although ... is real analysis useful in differential geometry?

the late great, Wednesday, 18 December 2013 18:57 (ten years ago) link

yes

flopson, Wednesday, 18 December 2013 18:57 (ten years ago) link

pairing of most similar would be cubes + discrete, diff geo + ana

flopson, Wednesday, 18 December 2013 18:57 (ten years ago) link

oh okay. that's what i'd do then.

(higher math n00b)

the late great, Wednesday, 18 December 2013 18:58 (ten years ago) link

cube complexes was developed by algebraic topologists & geometric group theorists, people who exploit an analogy (functor or whatever) between topological spaces, infinite groups, and cayley graphs of infinite groups, to prove results in group theory & 3-manifold theory. so graph theory would come up

flopson, Wednesday, 18 December 2013 18:59 (ten years ago) link

the simplest vers of diff geo is, like, in multivariable calculus taking a surface integral

flopson, Wednesday, 18 December 2013 18:59 (ten years ago) link

yeah that's about as far as i got in geometry

the late great, Wednesday, 18 December 2013 19:02 (ten years ago) link

that article i posted upthread goes into the CC stuff, with some quotes by dude who is teaching the course (and is like world champion of cube complexes)

flopson, Wednesday, 18 December 2013 19:03 (ten years ago) link

yeah i read it but my head started to spin halfway through and i definitely got real confused around when the cube complexes came in

the late great, Wednesday, 18 December 2013 19:04 (ten years ago) link

word

flopson, Wednesday, 18 December 2013 19:06 (ten years ago) link

2 much cool math

flopson, Wednesday, 18 December 2013 19:14 (ten years ago) link

How can you not take Erdos class?

The Glam Of That All The Way From Memphis Man! (James Redd and the Blecchs), Wednesday, 18 December 2013 19:51 (ten years ago) link

i know, right

flopson, Wednesday, 18 December 2013 20:09 (ten years ago) link

Students who will make significant progress towards the solution of any open problem on the list posted here will get the grade of A+ regardless of their numerical score.

flopson, Wednesday, 18 December 2013 20:16 (ten years ago) link

This is kind of old news, but I enjoyed this article. I never tire of these kinds of stories about unknown mathematicians toiling on hard problems in obscurity for years and then reaching a breakthrough, plus it does a good job of explaining the topic in layman's terms:

https://www.simonsfoundation.org/quanta/20130519-unheralded-mathematician-bridges-the-prime-gap/

o. nate, Wednesday, 18 December 2013 20:29 (ten years ago) link

yeah that one's great

flopson, Wednesday, 18 December 2013 20:32 (ten years ago) link

there was a great slate article where they explained why twin primes conjecture is an obvious conjecture (because primes behave *as if* they are randomly distributed, even though they're not)

flopson, Wednesday, 18 December 2013 20:33 (ten years ago) link

this interview with the guy is awesome http://nautil.us/issue/5/fame/the-twin-prime-hero

lollercoaster of rove (s.clover), Wednesday, 18 December 2013 22:22 (ten years ago) link

I am working on a problem related to the Goldbach conjecture.

TIL

Allen (etaeoe), Thursday, 19 December 2013 13:37 (ten years ago) link

flopson: what courses did you end up registering for? Real Analysis 4, I hope. :-)

Allen (etaeoe), Thursday, 19 December 2013 13:57 (ten years ago) link

i have until third week of the semester, probably gonna feel it out. not sure if ana will work out though, it's a pretty heavy workload

flopson, Thursday, 19 December 2013 15:25 (ten years ago) link

you like analysis?

flopson, Thursday, 19 December 2013 15:28 (ten years ago) link

One of the songs on Fade I don't care for, but the math is very good:

https://www.youtube.com/watch?v=4IwA9IimYSc

clemenza, Monday, 23 December 2013 13:40 (ten years ago) link

Reminds me I need to change my screenname.

The Cantor Dust Brothers (James Redd and the Blecchs), Tuesday, 24 December 2013 02:40 (ten years ago) link

HI DERE

The Cantor Dust Brothers (James Redd and the Blecchs), Wednesday, 25 December 2013 20:39 (ten years ago) link

merry xmas math nerds

flopson, Thursday, 26 December 2013 05:05 (ten years ago) link

^ let xmas be any holiday

j., Thursday, 26 December 2013 05:15 (ten years ago) link

man this thread needs some actual words in its title

i cracked open a graph theory book, been doing some problems to relax

i realized that when i tried to 'write math', i automatically write a symbol (kind of a backward epsilon, though it was never quite that before when i used it) for 'such that'—which i/we NEVER do now when writing logic.

what is wrong with logicians?! why don't they write it? ('logically unnecessary', prob.)

j., Sunday, 5 January 2014 04:14 (ten years ago) link

do you mean existential quantification? as in ∃ x. x > 5 ?

You need it in higher order logic obv, but it tends to be implicit in first order logics.

lollercoaster of rove (s.clover), Sunday, 5 January 2014 05:27 (ten years ago) link

yes, i mean after the quantifier and before the statement of the condition involving the bound variable

j., Sunday, 5 January 2014 05:32 (ten years ago) link

ah, as opposed to just the dot?

lollercoaster of rove (s.clover), Sunday, 5 January 2014 05:44 (ten years ago) link

yeah; we certainly never used dots in any of the informal math style/notation i learned. backwards 'epsilons' or words.

j., Sunday, 5 January 2014 05:52 (ten years ago) link

maybe it's because logicians tend to be writing formulas after quantifiers which they just intend to be satisfied by values for the relevant quantified variables,

whereas a mathematician writing down an existential quantifier usually intends the subsequent conditions to say something meaningful about the 'x' (etc.) whose existence is being asserted (usually in terms of some conditions stated initially, or a principle or theorem etc.), so that he reaches for a piece of notation that emphasizes the subordination of the condition to the existential quantifier.

(i find that when i'm writing math, i will even put in a comma after a universal quantifier, for somewhat analogous reasons maybe)

j., Sunday, 5 January 2014 05:58 (ten years ago) link

do you mean '∍' ? I think that it might have to do with set theoretic roots there. You can read it as there exists an x drawn from the set of 'x > 5' for example. But if you're working without a set-theoretic model in mind then its terribly confusing. or if you have exists x ∍ R, then that's more like giving a 'type' than a condition -- x drawn from the reals.

lollercoaster of rove (s.clover), Sunday, 5 January 2014 06:27 (ten years ago) link

i do mean that, but in concert with a membership epsilon, and w/in the general background of a naive set theory (the 'jargon of mathematicians' kind)

so it may be e.g. there exists x epsilon R backwards-epsilon x > 5

j., Sunday, 5 January 2014 06:35 (ten years ago) link

I wasn’t familiar with ∋ in a set-theoretic context. Nonetheless, Wikipedia’s article on Elements: http://en.wikipedia.org/wiki/Element_(mathematics) mentions it:

Another possible notation for [x ∈ A] is:

A ∋ x

meaning “A contains x”, though it is used less often.

I assumed you were talking about the traditional notation for “such that.” Most contemporary mathematicians, however, use a semicolon.

Allen (etaeoe), Monday, 6 January 2014 03:38 (ten years ago) link

The relevant Unicode code point: http://www.fileformat.info/info/unicode/char/220b/index.htm

Allen (etaeoe), Monday, 6 January 2014 03:39 (ten years ago) link


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