Mathematics - 2021-07-17 (page 1 of 3)

user178758

00:00

re: Step 1

leslie townes

call an attorney is step 1. :)

user178758

perhaps, that should be Step 0?

leslie townes

yeah.

one of my advisor's other students did nothing but employment compensation advising and litigation.

he is retired now.

user178758

have you ever thought of doing an MBA?

AMDG

~~I prefer to represent integers in the form of the infinite decimal expansion of nine ninths.~~

Ted Shifrin

00:12

I removed my answer. It was in fact not a counterexample. More thought is required.

AMDG

This might seem silly, but is there a nice trick for multiplying by either zero or one using logical arithmetic?

Preferably using two or fewer logical operations.

Three cycles is relatively expensive for such a simple operation.

If not, I can just use a conditional mov.

leslie townes

01:13

multiply the contents of a register by 1 using nop

i did think of doing an MBA. the debt burden is kind of a scam though.

the jd debt burden was more than enough.

Quin

01:38

I feel like such a creep proctoring exams on zoom lol. i cant wait to get back to classrooms!

Chairman Meow

01:54

Is there anyone around that can help with a stats experimental design problem?

robjohn

02:47

@TedShifrin It was put on the low quality queue automatically, probably because of its length, but it passed muster with 2 "looks ok" votes.

I don't know why anything needed to be said about it.

Prateek Mourya

What function graph is this

robjohn

@PrateekMourya Looks a bit like $\frac{\sin(r)}r$

hard to tell with so little of it shown

Prateek Mourya

03:09

Wolgwang

Spontaneous symmetry breaking

copper.hat

03:47

@TedShifrin silliness.

user777

04:03

Hi! I have a question: First from this article:

https://www.quantamagazine.org/how-many-numbers-exist-infinity-proof-moves-math-closer-to-an-answer-20210715/

This new article states that the paper by David Asperó and Ralf Schindler show Martin’s Maximum and Woodin’s axiom implies each other. Note that if one of them is true, then continuum hypothesis is false.

My question: Why don't we add Woodin's axiom or Martin’s Maximum in ZFC axioms and show that continuum hypothesis is false and we are done. Why don't we say that continuum hypothesis is no longer true? What is left to show?

Note that Godel said in paper in 1947: "the role of the continuum problem in set theory will be this, that it will finally lead to the discovery of new axioms which will make it possible to disprove Cantor’s conjecture". So, what is the problem of adding Martin's Maximum in ZFC axioms?

Ted Shifrin

05:15

@copper.hat Well, in hindsight, I was wrong, so deserved punishment.

copper.hat

06:02

@TedShifrin punishment is a bit severe...

robjohn

@PrateekMourya The closest I could get simply was this.

leslie townes

that is way too set theoretic for me to comment on, user777.

i TAed for woodin a few times. one reason for not adding it to ZFC is that he has enough professional accolades already.

robjohn

@leslietownes what is this "enough" of which you speak?

leslie townes

yeah, i dunno.

he was a really nice guy. i'm not sure i would have taught the classes the way he did, but he was thinking about it and being consistent and doing his best, which is more than you can say for many Big Names.

robjohn

06:17

Yeah, I proved the Riemann Hypothesis today, but I think I've done enough already, so I'll just leave it be.

leslie townes

i did meet a few people along the way who took the attitude of, i got tenure so i'm going to put my feet up. my wife works with a bunch of them. i go between sympathizing with them and hating them.

in conclusion, leslie is a land of contrasts. thank you.

copper.hat

F. Scott Fitzgerald: The test of a first-rate intelligence is the ability to hold two opposed ideas in mind at the same time and still retain the ability to function.

The Riemann Theorem as it is now called.

Koro

@copper.hat Hi.

I think that $A(x_0-a)\lt 1$ is unavoidable

copper.hat

it is the nature of things :-)

Koro

But my question is specifically about convergence of $x_n$.

I understand that the sequence is not required to be considered at all

and that there are ways to solve the question without sequences at all but for my own understanding I want to know a counter example to $x_n\to a$

Pythagoras has already given a fantastic proof to the theorem I was trying to prove

and copper, you also suggested one proof. but the question is of $x_n\to a$ or not.

Linking the question again to avoid too much scrolling:

4

Q: Proving convergence of a sequence $\{x_{n}\}$ satisfying$|f( x_{n}) |=|f'( x_{n+1}) ||x_{n} -a|$,where $f$ is a function satisfying some conditions.

Theorem: Let $\displaystyle f:[ a,b]\rightarrow \mathbb{R}$ be a function differentiable on $\displaystyle [ a,b]$ such that $\displaystyle f( a) =0$ and that there exists $\displaystyle A\in \mathbb{R}$ such that $\displaystyle |f'( x) |\leq A|f( x) |$ for all $\displaystyle x\in [ a,b]$, then $...

copper.hat

06:31

my first comment to your question addresses that i believe? if $f(l) = 0$ then you can show that $f(x_0) = 0$ which gives you a contradiction.

i am not sure that you can show that $x_n \to a$.

Koro

06:45

copper, I understand you point: if $f(l)=0$ and that $A(x_0-a)\lt 1$ then clearly $f(x_0)=0$ and here no where we required $x_n\to a$ (because $A(x_0-a)\lt 1$) and therefore it may not be necessary that $x_n\to a$ for the theorem to hold. And such a choice of $x_0$ is always possible as if not then $f$ is $0$ on the given interval.

thanks a lot copper.

@copper.hat i'll think more about showing the convergence part (as still it is neither been proven nor disproven)

copper.hat

07:08

@Koro probably not really worth it as you are shooting for a contradiction anyway.

Koro

@copper.hat :) yeah right. Also, now I don't have enough reason to believe as to why $x_n\to a$ will be true. there may be a case when $f$ is zero on $a\le t\lt c$ for some $c$ then $x_n$ may converge to $c$. This was also pointed by Pythagoras :)

leslie townes

i spent about half of my month's child tax credit on sushi, so you're welcome, america.

copper.hat

we met some friends for dinner tonight is a local italian place. not especially fancy (cucina on solano), it came to $150 and our friends were sharing an entree. prices have gone up in the last while!

sinful amount of $ on food.

leslie townes

i gave exactly one dumpling, which we had as an appetizer, to my daughter, who took one bite, rejected it, and then minutes later demanded more of the 'meatball'

she can say 'gyoza' now. she is learning new words.

copper.hat

potsticker in our house

leslie townes

07:20

that's what they called them at king tsin.

Koro

150 $ ??

leslie townes

she has had nigiri sushi and liked it but only salmon. not other fishes. she spat tuna out.

copper.hat

yes. i mean it was not a particularly fancy place

i like tuna, but salmon would be my fave

must be an irish thing :-)

salmon & blackberries feature in old stories

Koro

copper, i mean 150$ is very expensive

leslie townes

i thought yellowtail would be a simpler option.

Koro

07:22

for dinner

copper.hat

well, i am ashamed to say that i have had many meals that cost much more than than.

leslie townes

it's relative. 150 can be very expensive at a not too fancy place, at others it would be a steal.

copper.hat

however, a few years ago i took my entire irish family & kids out to an italian place in cork for about the same in euro.

leslie townes

which, knowing the irish, was probably about 30 people.

copper.hat

in '90 my self & a coworker rewarded ourselves with a nice $200 meal after a long day of getting the demo ready at a trade show.

involved some nice port as well.

i have turned back bottles of wine costing similar amounts.

for a lark.

long story.

leslie townes

07:24

i actually wonder what's the most i've ever personally racked up in a dinner. i'd guess $150 or so.

very special occasions. normally i eat for $10 or less.

copper.hat

i think if we eat out (as in take away) we average $15pp.

leslie townes

takeout. not take away

stop trying to be english

copper.hat

:-)

leslie townes

having a kid has complicated our food expenditures because we don't always know what she'll like. sometimes we buy two things and one of them doesn't work and then we have to eat it.

tonight she had vegan macaroni and 'cheese', some raw carrots, and a side of sweet potato fries.

copper.hat

yeah, that complicated life. also, my wife got it into her head that my daughter had wheat allergies so we spent a few years avoiding wheat which was a total pain.

leslie townes

07:31

my wife has sensitivities, which are not quite allergies, to all dairy, potatoes, and wheat. which means that everything she eats is disgusting.

copper.hat

my daughter liked squid tentacles when she was 3-4 yo.

leslie townes

i love squid and octopus. someone was telling me the other day there's some ethical issue with octopus because of how smart they are. what about how delicious they are?

copper.hat

ohh, potatoes would be a deal breaker

they are at the cat/dog level i thought?

leslie townes

yes, basically. i try not to think about it.

and maybe i also have an ethical issue with deciding how OK it is to eat something based upon how smart it is. debate me on that front, please.

copper.hat

it seems a little unfair to favour some because of their smartness :-)

bingo

leslie townes

07:34

exactly.

copper.hat

i hear kale is very intelligent, so i am avoiding

leslie townes

i only eat kale that hates itself and wants to die

copper.hat

:-). the risotto & scallops was delicious tonight though

leslie townes

risotto sounds really good right now.

copper.hat

the thought of it required me to find some leftovers in the fridge to fill the gap...

leslie townes

07:43

my in-laws love this place near their house, it's absolutely horrible for everything other than cacio e pepe which is delicious.

it sometimes sparks conversation, why don't you get something else? there's no polite way of saying that i wouldn't eat what you're eating.

i have never in my life questioned someone's restaurant order. that is sacred to me. but others do it. you get something without meat in it, and people want to talk about whether you're a vegetarian.

i can think of 10,000 more interesting things to talk about than what i'm about to eat or why i eat it.

this might be a california thing. restaurant conversation about food preferences. just do your order and shut up and don't ask questions.

for more on this, consult my blog, "leslie speaks." at the $5/month sponsorship tier you get access to videos where i insult specific people.

copper.hat

yeah, food is calories for me. i don't get the fascination.

i don't like spending gobs of $ on it for many reasons. mostly guilt :-)

too many folks out there with very little. the priests got to me as you can see.

leslie townes

my wife's external family has amnesia about her food sensitivities and so everytime we meet there's a discussion of them. it is tiring. i also hate being asked if i'm vegetarian because i ordered a salad.

copper.hat

my hs was a Franciscan seminary.

leslie townes

$150 would go a long way at the food bank, copper.

copper.hat

i do give reasonable amounts very few months when it gets too much for me.

leslie townes

07:52

i only donate to food banks, other charities have too many layers of stuff and you never know what your money is going to.

in cash, not in kind, because they know what they need.

copper.hat

yeah, i've gone through the mill on that, and got scalped once.

leslie townes

half of our furniture is inherited from the berkeley st vincent de paul. it's "our" goodwill or salvation army.

copper.hat

it was an elementary school teacher at my kids school who was going to Afghanistan to do stuff (like building toilets)

i am a minimal kind of fellow. i d not like waste.

except if it involves convex analysis.

leslie townes

waste involving convex analysis is a consulting opportunity.

copper.hat

:-)

ive never really been paid directly for any maths contribution.

i fell like such an imposter

leslie townes

07:56

food banks are usually very efficiently run. there's minimal overhead and they are focused like a laser beam on what their clients need. if you try to get more direct it is a problem.

copper.hat

yeah, i have volunteered at the ones i donate to.

leslie townes

one time a woman in front of me at the grocery store didn't have enough money to pay for her groceries and i pretended to pick up $20 off the floor and said that she dropped it. she started yelling at me and wouldn't take the money.

so food banks it is.

copper.hat

funny. i have offered to pay at times, but people are sensitive.

leslie townes

i was trying to provide an avenue for, this isn't me doing anything, this is on the floor and it must be yours because it isn't mine.

copper.hat

i have on other occasions been a little rude and offered to pay if they will just move on.

leslie townes

07:58

i guess i made it too obvious.

ha, i've done that once.

here's $20 can i just get out of here.

copper.hat

i've become more patient as i grow older.

maybe just weak

leslie townes

i've found that too although i am not all the way there.

the zen state is still decades to come.

copper.hat

im tolerant if people are genuinely trying

leslie townes

there's less and less of genuinely trying these days. maybe i'm cynical.

copper.hat

like some folks get to teh register and then need to go away and pick something else. that bugs me.

leslie townes

08:02

that's the worst.

nobody who was properly raised would do that.

copper.hat

another peeve is folks trying to do exact change with their limited arithmetic when there is a big backlog line.

Leaky Nun

every action that inconveniences us is intolerable and inexcusable until we're the one doing the same action

leslie townes

leaky, you have a point.

copper.hat

do as i say, not as i do. my dad's line.

leslie townes

although i've never held up a grocery line trying to pay with a check made to cash from the bank of belize.

copper.hat

08:04

that's inexcusable @LeakyNun

i met a bunch of friendly sas soldiers in belize.

leslie townes

any time checking or coinage come out in front of me i go into a little bit of a negative mood.

copper.hat

technically i was sort of the enemy

@LeakyNun is your moniker something that is safe for work to explain?

leslie townes

one time i was behind a guy in CVS who was trying to do a money-changing scam, where you confuse the checker with varying requests about exchanging dollar amounts for other dollars. the checker was frozen. i thought i should say something but didn't.

Leaky Nun

@copper.hat anagram of my real name

copper.hat

duh. slow here. never occurred.

leslie townes

08:07

i was thinking, i know exactly what this guy is doing, and he is getting over the CVS corpoeration in the amount of $15 right now.

i just stood there.

copper.hat

intent to defraud

leslie townes

the guy was really good at it. he was basically giving a class in how to do it.

i had this thing where i was torn between, stop a crime or just not snitch. it wasn't coming out of the checker's paycheck (probably?) so who cares.

copper.hat

at horse races there used to be collections of scammers

gives one a spidey sense

leslie townes

they wear a plaid uniform and have inside information about the horses.

copper.hat

and shells with peas

leslie townes

08:11

one time late in college i was on a date and i saw a guy steal my date's wallet and my no-snitch instinct caused me not to say anything and then the date ended because she couldn't pay for something. lesson in there somewhere, for someone.

the guy was clearly going through hard times and i don't know how we would have detained him in the coffee shop. it seemed pointless

so i just said nothing.

this is a pattern with me

copper.hat

there have been a few pickpocket attempts on me over teh years

leslie townes

i stopped one by saying "put it back." they are not violent criminals.

copper.hat

belize city was one particularly sensitive one

new orleans was another

countless times in paris & italy

surprisingly never in ireland

leslie townes

i respect pickpockets and other nonviolent criminals. mainland europe is swarming with them. if they get over on you, that's on you.

we had a guy break into our house once. he left when my wife screamed at him. they're not violent people.

copper.hat

they bug me

i can get a little 'agitated'

had two guys try to steal my backpack at the university ave mcds years ago

leslie townes

08:16

that's what i like about them. when they understand someone is about to get agitated they go away.

copper.hat

one was trying to distract by asking directions

leslie townes

classic.

copper.hat

i was trying to help, so i turned to get a map from my pack and caught the otehr guy

then i went balistic, the mcds manager just hid

leslie townes

one time someone was smoking on the porch of my house and i told them to go away, and they said, call the police, and i said, i don't call the police, you're going to call them on me. away they went. didn't have to prove the point.

copper.hat

the two left quickly while shouuting. i was a little younger and faster i those days and i think they realised i was not domesticated.

leslie townes

08:18

i somewhat appreciate nonviolent, silent, non-victimizing crime. i don't really care if someone steals my wallet.

copper.hat

just stealing some cash doesn't bother me that much. having to cancel cards, replace my bike link, etc etc, well, that really gets to me

leslie townes

that sucks. my wife has had her identity stolen several times.

she's had like 4 social security numbers.

copper.hat

wow. that must be confusing for many reasons. does ssa move her records to the latest one?

how come so frequently?

leslie townes

well 4x over 20 years and we don't really know why. i do think someone at her current job sells them to people.

copper.hat

time for my ugly sleep.

later!

leslie townes

08:21

gute nacht.

copper.hat

oiche mhaith agat

Wolgwang

08:33

Is it normal for a question to get 3 upvotes in ≈30 seconds?

leslie townes

seems weird to me but i do not have any understanding of the underlying analytics.

user178758

(removed)

user178758

10:05

New Community VP seeks your input - what should we be looking to change and what is inviolable?

Prateek Mourya

11:01

Thanks @robjohn + @Wolgwang

AMDG

11:58

@leslietownes How does that work?

All that does is increment instruction pointer

It's only useful for padding code.

robjohn

@leslietownes using that criterion, there would be a lot of people that could be put on the menu...

user178758

13:04

TIL

in Kick me, Jul 5 at 23:53, by hyper-neutrino

Don't kick people more than twice daily. Kicking a user three times will raise an automatic moderator flag.

cc @TedShifrin^

et al

porridgemathematics