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03:00 - 16:0016:00 - 22:00

03:25
the one who will say no memes here is most probably a discord mod
i think they all have better s--- to do, man, you might have gotten away with this one
bruh bruh bruh bruh bruh bruh bruh bruh bruh bruh bruh bruh bruh bruh bruh bruh bruh bruh bruh bruh bruh bruh bruh bruh bruh bruh bruh bruh bruh bruh bruh bruh bruh bruh bruh bruh bruh bruh bruh bruh bruh bruh bruh bruh bruh bruh bruh bruh bruh bruh bruh bruh bruh bruh bruh bruh bruh bruh bruh bruh bruh bruh bruh bruh
the actual kids say "breh" now
i never felt younger than when a teenager referred to me as 'breh,' as in 'sup breh'
instantly lost about 15 years of age
03:30
he1/2he1/2
i made a new script for writing
That explains your bratty behavior.
hehe
truu
maybe i should change
i should be like i was 6 months ago
but no
this is permanent
you have the ingredients of a socially responsible person and a contributor to society.
instead, you have chosen this path
what has been done cannot be undone
i have left mathematics nowadays
me too. i don't learn anything new i just replay the classics.
03:38
i am into reading old texts
i'd forgotten that i still have hille and phillips 'functional analysis and semigroups.' it is a good textbook.
olivia says hi.
looks like the cat is about to make a meal of the doll
i was in a different tab and at the first glance i thought that something is eating the baby
my cat is about as well-adjusted as i am.
03:44
cats always end up hurting me
olivia bites us all the time. usually when we are going up or down the stairs. that's when we're vulnerable.
my cat is a veteran
she is russian
you'll be about halfway down the stairs, they're split up into two flights, and suddenly a black flash out of nowhere will bite you in the leg and run away.
i don't know why people live with cats.
cats4life
i dont like.... i dont like dogs
i like dogs but am probably more of a cat person.
03:55
@leslietownes vampire cats and unfortunate toddlers.
i do think cats have some kind of spiritual connection to evil.
it might be why i like them
we have 3 cats, 2 dogs, and a bunny.
i went to a restaurant the other day for my anniversary and the fiercest looking pit bull you have ever seen ran up to me and licked my hand. i have a soft spot for pits.
we like animals, cats, dogs, rabbits, birds (we had a toucan years ago)
one of my friends owns i think five rabbits now and also volunteers time at a rabbit rescue.
rabbits are something i don't understand.
03:58
they are for turning vegetables into pellets.
once you come to understand that, you will understand bunnies.
ma kat haz 4 childrin
another of my coworkers owns two rabbits. they have taken their enthusiasm for rabbits to the verge of intemperance.
do you know why socrates became a philosopher
i like to flatter myself by thinking i have both a good wife and am a philosopher.
nae
describe your philosophy
04:06
you may have caught me out on this. i mostly just talk nonsense.
not more than me
i am the god of nonsense
i may do less on the internet. i do a whole lot of texting nonsense.
04:23
i have a preference for dogs.
that said, my last encounter with a pitbull left my jeans ripped and a number of puncture wounds in my leg.
pit bulls come in two varieties, lawful good and chaotic evil.
not just pitbulls, my last encounter with a poodle followed similar lines, except i was wearing shorts while cycling.
poodles are way too smart. i don't trust them. they're barely dogs.
the owner was mortified and very understanding
its never about the dogs. its about the owners.
i love bri'ish english
american english is a load of old cobblers
04:26
that's definitely it. and people are more likely to mistreat 'fierce' dogs.
bri-ish is an example of what linguists would refer to as the glottal stop.
my daughter has moved into an apartment in london for the summer, unfortunately one of her housemates likes to smoke pot which nauseates my daughter.
i make have to take the hit for the lease. learning lesson.
the housemate should not do that. marijuana has an irritating smell. you can get the same thing out of edibles.
if only i had a fraction of her chutzpah
there was no no smoking clause
my wife had this at her last non-academic job. there was someone who was constantly smoking weed in the bathroom, and it gave people headaches.
she didn't say anything because she didn't want to be a narc, but it was bad behavior.
it was really self-centered stuff and it was annoying that my wife was questioning her own sanity about maybe not wanting that around the workplace.
history is written by the victor
04:34
i prefer to concentrate on now and not the writing of history.
when we looked at the storage space above our garage upon buying our house we discovered the remnants of a grow operation.
i may fly to see her. i miss her.
i don't think i could ever put up with my daughter being in a different time zone. time may change that but for now i like her right down the hall.
my mother said that the day i left was the worst day of her life.
this is payback i suppose.
my mother did not say that.
04:39
i had no idea what i was inflicting on her. i do not want my daughter to either.
@leslietownes you never know.
my mom has lived with my sister because of the pandemic. they get along better than i do with my mom.
the downside of being irish is a tremendous capacity for being stoic.
i've cried when a cat died but not when relatives have. the whole family shows up and nobody shows any emotion.
it's dysfunctional and it was internalized very early.
took me a while to learn that
it is a defense mechanism for a society that lost a lot at one stage
can you imagine the famine. something like 10% of the population.
04:43
before the famine it was 8m. after 4m. 1m died, the rest left.
i had my grandmother explicitly tell me never to express any feelings.
mostly to britain
we had an odd mix growing up. generally feelings only shown to the very young.
we are undoing all of this with my daughter, she is very open about everything.
my grandmother said something like, nobody is alive forever, and you can't be bothered to feel anything about anything that happens on earth because none of it matters. and then some catholic stuff i forgot.
i remember some of it at christmas and easter.
my daughter's very open about everything and she yells at me if i don't reciprocate.
she will be the emotionally healthiest member of the family
i always viewed religion in the same way as santa claus, so a lot of that rubbish did not really sink in.
i try to be open with my kids. it is harder than i expected at times, especially with my son.
i was very much trained not to be expressive. i don't have a boy, but if i did i don't know what i'd say to him.
04:50
ireland doesn't really have an explicit macho thing, but there is some other no feeling thing especially between males in the same family
you just can't say anything.
luckily we have his upcoming driving test to discuss :-)
and my umpteen flaws as an instructor :-)
i reckon if each generation makes an improvement then we are doing ok
my kids are already way ahead of my on that front
so i reckon i am doing ok :-)
wow, i'm not even drinking yet
see, any serious statement needs a follow up to cast doubt...
and weirdly ireland produces many of the most expressive artists.
i think behan said that one needs to suffer to produce
he was a pretty amazing fellow for a low key guy
i think music, etc is an outlet
moynihan said to be irish is to know that in the end the world will break your heart
i love how he works resentment against the church into a beautiful poem
04:58
it is scary how much that poem reaches into my own life
i really did not get poetry until my 30s
i'm waaay behind on my psq quotient
you need to begin racking up new reputation points.
i have heard that martin luther had ocd
he had intrusive thoughts
about god
which martin luther?
sr.
lol
i mean not the junior one
you are stepping into an intense irish moment
05:02
hehe
it always amazes me when people ask a question without even trying basic examples.
3
my stock answer is "Consider diagonal matrices."
mine is to try the $1 \times 1$ matrix $x$, but it usually degenerates into something like 'that is not a matrix'.
consider 1x1 matrices is insulting. you should offer them the option of considering diagonal non-1x1 matrices.
"try 1", "try 0", "try identity matrix", "try zero matrix", "try a unit vector", "try a 1x1 matrix" solve like 90% of the questions i have to myself
i just think for 3 seconds, pick an example, and realize "wait of course, this is right/wrong"
05:09
it's a little goofy when a matrix question is not even a matrix question.
mod here
noooo
i think a lot of beginners think that simple numerical examples are a waste of time
I've computed:
$\pi(x) = \pi(\sqrt{x}) - 1 + \sum_{k = 0}^{\pi(\sqrt{x})} \sum_{\ell = 0}^{\pi(\sqrt{x})}(-1)^k{\pi(\sqrt{x}) \choose \ell }{\ell \choose k } \tag{5}$
Anything else we can do to reduce this formula or rearrange it?
what would $\pi(\cdot)$ be?
Prime counter
number of positive primes $\leq x$ any real number
05:11
I only do subprime stuff.
Made a post about it you can get to under my profile
@trollbot is this better?
and the rest are binomial coefficients?
Well that summation (if you see the derivation of it in the post) uses semiprimes intermediately
@leslietownes yes
05:12
is it a new formula?
The derivation is really simple
I've never seen this formula before
It's obviously recursive, which makes it difficult
Otoh, I got rid of the floors involved in such expansions usually
@leslietownes what are your thoughts on it?
there was a time when i was very good at simplifying/evaluating sums
but not now
Yeah, back in 1850 things were easier because the lower hanging fruits available
then the mathematicians came and took all the fruit from the tree
hhhhhaaaaaaahhhhhhhhhhhaaaaaaaaa
you
covid fruit bats
i will use the most insulting insult ever...
no u
that is easy for you
05:16
you are wasting space again
$\pi(x) = \pi(\sqrt{x}) - 1 + \sum_{k = 0}^{\pi(\sqrt{x})} \sum_{\ell = 0}^{\pi(\sqrt{x})}(-1)^k{\pi(\sqrt{x}) \choose \ell }{\ell \choose k } \tag{5}$ Can we do something with those binomial coefficients in particular?
why add a question to mse and then post it here a minute later?
It's an informal discussion here
Sometimes the room dies, and I guess I thought I would add a topic
Okay, I will go back to my MSE post since no one cares about prime numbers
we were all just waiting to leap on the question
05:20
every time someone mentions MSE here I have to remind myself it means math
everywhere else I go, MSE means meta.stackexchange.com
i meant mean square error
error?? what happened to robjohn??
@copper.hat you have aroused the angry euler now
surely you have other tricks? that is a bit jaded now.
@robjohn is flagging.
05:23
please don't spam zalgo in chat it's really old and uncreative and just annoying
oh wow
@hyper-neutrino What is Zalgo?
so its called zalgo
@copper.hat t̸̡̜͖͖̓̍̆̃͐̓͋͛́̄̆͘͝h̴͓͚͓̠͚͔̜̅͐̅̅́͛̀͑͆̋͝í̵̲̙̙̇͆͐s̷̢̛͕̦̯̊͌̇̃̒̅̆͗̈́̄̀̚͝͠
some indian mathematician 'solved' RH
i dont believe it
why does this happen every year
05:24
you need to read more up to date news.
isn't the solution already known to be invalid
like i thought this was mentioned like 2 days ago here
i was in a cave recently
fighting some amerikanzis
yep, its old news here.
i think it is fair to say that one can dismiss any claims in regard to the RH
yup
i sometimes think that i am a bit too skeptical
the $1m prize attracts a lot of quacks.
05:27
whenever i see an 'RH proof' on the internet i immediately say w r o n g
well, that'd give you a 100% success rate so far :P
its easy to miss a perelman
but i dont think that any rh proof is right
there wouldnt be so many proofs if the prize was $10
there are no proofs.
 
3 hours later…
08:03
@copper.hat eh?
man
i want to forget many things
In the last answer, why is $j\le \sigma^2 (j)\; \forall i, 1\le i\le 5$?
wish i could
these thoughts always disturb me
i can see a cat on the world map playing with Australia
@Koro what happens when you set $j=\sigma(k)$?
$\sigma^{-1}(j)\le\sigma(j)\iff\sigma^{-1}(\sigma(k))\le\sigma(\sigma(k))$
09:11
:-)
😊
I got it. Many thanks @robjohn :-)
09:24
Hello!
Here's a problem that I'm trying: **Problem**: Suppose $f$ is continuous and periodic on the reals with period 1. Prove that if $\alpha\in[0,1]$ is an irrational number, then

$$\lim_{N\rightarrow\infty}\frac{1}{N}\sum_{n=1}^N f(n\alpha)=\int_{0}^1f(t)dt$$

Hint: First consider $f(t) = \exp(2\pi ikt)$ where k is an integer.

---
**Attempt**: I have verified the equality for $\exp(2\pi ikt)$. I know (Theorem 4.25, Big Rudin) that for any continuous function $f$ and any $\epsilon > 0$, we can find a trigonometric polynomial $P$ such that $|f(t) - P(t)| < \epsilon$ for all $t\in\mathbb R$, whe
More readable here: mathb.in/59441
Could you share your thoughts on how to complete the solution? I think I'm almost there.
09:47
Some more simplification due to uniform convergence: mathb.in/59443
Now we only have to show that the limits on the LHS can be swapped. How?
10:06
The fact that this question: math.stackexchange.com/questions/482599/… was closed got me thinking: Is there a need for a "mathematical proofs" stackexchange? I think the stackexchange format would lend itself nicely to a proof collection in contrast to proofwiki.org/wiki/Main_Page you would have a natural "statement" (the question) and "proofs" the answers, and people can comment on proofs for clarifications, corrections, etc.
the upvote system is also lacking in a proof wiki
what do you think?
is it obvious that this P will satisfy the above inequality?
any tips for going about showing it I dont remember strategies for showing this matrix inequalities
10:45
@robjohn Thanks. It is a bit ambiguous which variable is meant with $o$, since $cx$ is also a variable for a constant $c$. My notation here first assumed $cx$ was the variable and then $x$, which is confusing. My short proof here assumed $cx$ was the variable, but then the limit was taken with respect to both $cx$ and $x$, which is not very consistent.
 
2 hours later…
12:57
@epsilon-emperor fix N such that $\forall n>N$ the difference between the sum and the integral is less than some $\epsilon>0$
Perfect. That's exactly what I did, and it all worked out :)
Thanks!
cool
13:34
Any interesting/inspiring improper integrals? Gabriel's horn is the only one I can think of.
$\int_0^{\infty}\frac{\sin(x)}{x}dx=\frac{\pi}{2}$
@Thorgott can you do that with a first year understanding of calculus?
I think residues would be easy to do it.
I should add that I am asking this for possible use with first year math students. :P
improper means convergent but not absolutely convergent? Or just integral over a non compact domain?
îf they're willing to take differentiation under the integral in good faith
Usually non compact. At least how I have seen it used.
13:42
Gaussian integral comes to mind then
Oh that is a good one!
and with that I think we've covered the most theoretically important ones
it's also a good thing to get familiar with the Gaussian integral early in there studies, as it pops out about anywhere in science
13:54
Definitely right about that Astyx.
Joe
Joe
@leslietownes: I've finally found a reference that uses the CORRECT™ definition of strictly decreasing: Terrance Tao's Analysis I. I've updated my answer.
Did Daminark perish, or is he still alive?
@Joe what references use an incorrect definition?
Joe
Joe
@anakhro: I was being half-facetious when I said that. It transpires that a number of authors (including Spivak and Rudin) only define "monotonocity" on intervals. By that definition, whether the function $f(x)=1/x$ is strictly decreasing is undefined. You can read my answer for more details
14:10
I see. That's interesting that they seem to always specify "interval".
Hairer-Warner use the "correct" one, too.
Joe
Joe
@anakhro: I think it's because some of the main theorems in this topic are about functions which are monotonic on an interval. Still, that's no reason to make the definition itself so restrictive
Yeah, kind of weird. Abbott's analysis also uses the general definition.
Joe
Joe
@anakhro: I like that book, a lot, actually. Very underrated
You find it is underrated? I find it's the number one suggestion people give for an intro to analysis.
Joe
Joe
@anakhro: I guess I see people often being pushed towards the "classics" like Spivak or Rudin, but it's good to know that Abbott's being given some recognition
14:19
Rudin I see suggested most often by sadists.
Does Spivak count as an "analysis" book?
Joe
Joe
@anakhro: I think so. Depends what you mean—in the UK, it seems like anything with $\varepsilon$'s in it is called "analysis"
Heh, doesn't stuff like Stewart's calculus have $\varepsilon-\delta$ arguments for limits and stuff for the sake of including the formal stuff in introductions?
Joe
Joe
@anakhro: Yeah it does. The course I first did at school had nothing of the sort, which is quite sad really. It was a highly calculation-based course. That made no sense—if you wanted to become a mathematician, then it didn't have anywhere near enough rigour; if you wanted to become an engineer, then it overlooked the fact that engineers often don't do calculations by hand—there's this thing called Wolfram Alpha for that
Yeah, calculus needs to be fixed.
Joe
Joe
14:34
@anakhro: I think the sad truth is that many (most?) secondary school teachers wouldn't be equipped to teach a completely rigorous calculus course
Well I don't think a rigorous calculus course should be taught in high school.
Joe
Joe
But we definitely do much better
Save analysis for university.
Joe
Joe
@anakhro: On second thoughts, I agree with you that rigorous calculus shouldn't be taught at school. But there's not enough emphasis on building understanding or intuition either
I agree there. So then the question is how do you build understanding/intuition without forcing students to take a course they don't want/need, meanwhile being engaging and accessible. Should be a Millennium prize problem.
Joe
Joe
14:42
@anakhro: Haha, indeed it should. Sorry I need to go, but it was nice talking to you
You too, enjoy your day!
15:05
@Astyx the Gaussian integral is easier if you have multivariable calc, not sure what level anakhro's class is.
(change of variables in 2 dimensions)
Yeah, I realized you had to do polar coordinates or something.
That is the usual way to evaluate that integral
15:38
@robjohn Some silly word play on the flag on your avatar :-)
one of the calculus teachers at my high school had never taken calculus. it was painfully obvious.
@copper.hat Ah, I had removed the flag a little over an hour before that, but unless you refreshed, you would have still seen it.
@leslietownes ouch
It still shows, I guess I should refresh more often :-)
he could do the power rule for differentiation. that was about it.
that won't get you too far
15:48
he let the better students teach the class, which was actually fairly effective, but maybe not the best use of taxpayer dollars.
we also had a german language instructor whose main qualification was a german surname. she had probably taken it in high school. hopeless.
sometimes the lack of resources was good. the honors fourth year spanish class was the freshman spanish for spanish speakers class (our high school had a lot of resources for new arrivals from mexico). much more effective than textbook based instruction.
We had no calculus classes at my high school. We had to go to the community college to take calculus.
critical skills like piloting & teaching at the primary/secondary level should be evaluated regularly in my opinion.
i could rant for hours about it but K-12 has been poisoned by ed schools and educational theory. at least in math.
there are reputable people who don't think that subject matter competence matters very much.
The way people drive around here, I would believe that the requirement for a driver's ed teacher be that they know the difference between a car and a dog.
our school cut driver's ed. lack of funding. explains a lot about the traffic in my hometown.
15:52
"you got two out of three... you're in"
@leslietownes driver's ed has not been in school here for over 15 years.
just give me the money, who cares about capabilities
there was something else they cut that used to be a mainstay. shop class. woodworking and the like. a vocational high school opened and they just moved it over there.
some cost cutting genius
some of the kids in that class were really talented. professional level stuff. it was probably the only thing about school that interested them.
apparently my high school has a computer science class now. i wonder what that's like.
certainly nobody was qualified to teach that in my day. they had one IT guy and he 'outsourced' most of his work to students. i spent several days installing ethernet cards in a bunch of PCs on the day that the internet came. i should have been compensated.
each department had its own set of computers, moving the equipment was such a pain in the ass. they should have just had one computer lab. nobody did anything on computers then.
03:00 - 16:0016:00 - 22:00

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