Mathematics

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Mathematics

$Mathematics$

Associated with Math.SE; for both general discussion & math questions alike. Just ask; don't ask to ask. Rarely if ever expressible as a ratio of integers. Chat guidelines: http://tinyurl.com/hzl2955 | $\LaTeX$ in chat: http://tinyurl.com/cfqcvpc

3h ago – PM 2Ring

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PM 2Ring

07:09

Normally, most spam gets detected and deleted fairly quickly. But we've had a bit of a spike this month. metasmoke.erwaysoftware.com/graphs

rschwieb

yst 20:41

Hi all: I've got an announcement for interested parties. (I promise i really don't do this often.)

https://databaseofringtheory.wordpress.com/2025/02/15/help-choose-darts-200th-ring/

Ben Steffan

yst 19:03

it is our duty to clean up this mess so future generations don't have to suffer as much

Rakshith PL

yst 07:22

Cleo's mystery has been finally solved!

Ben Steffan

Feb 11 17:21

but I'm a crank, I'm a weirdo
what the hell am I doing here, I don't belong here :(

Thorgott

Sat 23:34

finally, real math

Ben Steffan

Sat 23:34

this is no ordinary typesetting. we're quantum-typesetting through the 5th dimension

pie

Sat 17:36

I am looking for a recommendation for a numerical analysis book. What book do you guys recommend?

one potato two potato

Sat 16:43

recently Hatcher uploaded a revision paper on arxiv

PM 2Ring

Fri 03:04

Soham Saha

Feb 13 09:47

Found a cool looking pattern.

Thorgott

Feb 12 15:48

oh duh

Thorgott

Feb 9 23:28

category theory is a field where most statements are kind of obviously true and the proof is basically forced upon you by virtue of basic syntax
higher category theory is a field where most statements are kind of obviously true but it took a decade to prove that

PM 2Ring

Feb 9 07:01

Happy Birthday, H. S. M. Coxeter!

PM 2Ring

Feb 9 07:01

Harold Scott MacDonald Coxeter

Harold Scott MacDonald "Donald" Coxeter (9 February 1907 – 31 March 2003) was a British-Canadian geometer and mathematician. He is regarded as one of the greatest geometers of the 20th century. Coxeter was born in England and educated at the University of Cambridge, with student visits to Princeton University. He worked for 60 years at the University of Toronto in Canada, from 1936 until his retirement in 1996, becoming a full professor there in 1948. His many honours included membership in the Royal Society of Canada, the Royal Society, and the Order of Canada. He was an author of 12 book...

Thorgott

Feb 8 03:19

TFAE:
(1) the lattice of subgroups is distributive
(2) every finitely generated subgroup is cyclic
(3) the group is a subquotient of $\mathbb{Q}$

Thorgott

Jan 27 21:15

clearly, one prime looks like the start of $\hookrightarrow$ and two primes look like the tail of $\twoheadrightarrow$

Ben Steffan

Jan 27 14:23

if you want me to take part in your psychological study you'll have to pay me

Thorgott

Jan 19 15:50

Ben Steffan

Jan 17 18:38

If somebody feels like helping you they will, but spamming is not welcome here.

hbghlyj

Jan 25 08:32

From the answer math.stackexchange.com/a/3743490 it is possible to embed Penrose triangle into curved three dimensional space, something called "nil geometry". I wonder if the impossible cube also can be embedded into curved three-dimensional space.

Xander Henderson

Dec 15, 2024 17:28

Why is epsilon afraid of zeta?

Xander Henderson

Dec 15, 2024 17:28

Because zeta eta theta.

Ben Steffan

Jan 22 15:13

the holy trinity: Obvious, Trivial, (removed)

Ben Steffan

Feb 1 22:04

@Thorgott auspicious

leslie townes

Feb 1 22:01

banach and tarski destroyed both the street price and the quality of the cocaine in 1920s lwow with their methods

Thorgott

Feb 1 15:37

also, I checked a reference, and $Wh(\mathbb{Z}G)$ is infinite for most abelian $G$ (any $G$ containing an element of order $5$ or $\ge 7$, for example)

leslie townes

Jan 2 20:55

email his children with accusations

Xander Henderson

Jan 30 02:01

@BenSteffan G-d, I hope not. Lungs work better in a slightly lower dimension.

Soham Saha

Jan 28 16:37

found a pdf of “Littlewood’s Miscellany” online, and it’s a really interesting read. I saw the book referenced in the Wikipedia article on “Ross-Littlewood paradox”.

leslie townes

Jan 27 23:56

when he's putting out his garbage someone needs to pop up out of the bushes and demand an answer from him

leslie townes

Jan 27 17:57

although there's also the trap of "i don't plan on doing this a lot so i'll just do it in ms office this one time" or "i don't have time to learn this week so i'll use MS this one time" and you blink and a few years later "this one time" was 20 times, you've wasted a nonzero percentage of your life on fiddling with word/PPT quirks, and you still don't know latex

Xander Henderson

Jan 27 16:33

@HomesickIguana That isn't how PhD theses work.

Thorgott

Dec 5, 2024 19:53

attention is for losers, make claims first, worry about details later

pie

Dec 23, 2024 15:20

PM 2Ring

Jan 25 16:05

Given any irrational real number $r$ it's possible to find a linear Diophantine approximation for any other incommensurable irrational $s$ in the form $z=ar+b$ with integers $a,b$ such that $|s-z|<\epsilon$ for any given $\epsilon>0$. I have a fairly simple algorithm to find $a,b$ pairs, based on the continued fraction convergents of $r$ and the extended Euclidean algorithm. But I'm not sure how optimal it is, and I'm curious about alternative algorithms.

weeab00

Jan 25 07:34

Any high-rep user can kindly share screenshots of this deleted question? math.stackexchange.com/questions/1821046/…

Ben Steffan

Jan 25 00:31

@Thorgott wrong answer. correct answer would have been "not much, how about you?" :)

Thorgott

Jan 24 21:14

@BenSteffan repeat after me: every homotopy type is 1-connected

Xander Henderson

Jan 24 15:42

You have better things to be thinking about.

Pizza

Jan 24 13:29

If someone keep cheating on all the exams, I wonder why hes still in university or college etc. Maybe he should think about whether this is really what he wants to do.

Soumik Mukherjee

Jan 22 08:44

What do those symbols mean?

Shaun

Oct 28, 2024 09:20

That's great, but given your track record, I suggest waiting a while before announcing you have proven it, next time.

Ben Steffan

Jan 21 21:18

mathoverflow.net/a/486394/142596 ?!?!

Jakobian

Nov 3, 2024 22:11

@DannyuNDos Tired of math? Study math

leslie townes

Jan 20 19:27

i don't mean to imply that definitions and hypotheses don't matter, but at the level of generality that people ask questions on MSE it is often the case that it sort of doesn't matter. i.e. if you aren't asking some question that depends on the details of the setup, then someone can assume whatever setup they like that is compatible with the question, and answer it in that setup, and everybody goes away happy

Thorgott

Jan 20 01:01

I mean, geometric arguments are neat (and I wish I knew more), but they're typically suboptimal for algebraic ends (though can be enlightening in other ways)

leslie townes

Jan 1 15:48

allow me to challenge the framing of this question, does it matter?

Thorgott

Dec 17, 2024 11:52

@XanderHenderson is this one of those "back in my days, to get to school I had to..." bits

Xander Henderson

Jan 19 16:10

This is my nightmare: