Mathematics

Andrew Micallef

12:01 AM

Well, I think I learned something here. And the main takeaway is stop "optimising". Cheers!

leslie townes

we humans are doomed to optimize the slowest parts of the system.

dc3rd

So I'm going to have to read up on Fisher's out of mathematics ideologies then huh? Reminds me of a BBC article about the most detailed atlas of the human body and how it was done in Nazi Germany, but the detail it presents is so good that it is still used today, but there is a large "moral quandry" about the whole thing

leslie townes

i think a lot of people in the 'first world' ~ 100 years ago were informally into eugenics and other stuff. which isn't to say they were raving nazis.

dc3rd

well didin't have to read far to find out about Fisher's beliefs.....second paragraph of his wikipedia entry.....

leslie townes

i do hope that if i'm ever written up on wikipedia, my bio doesn't include references to dr. mengele

we should not think of people as machines, and maybe the brightest of us should not imagine themselves as super-men or super-women or encourage others to believe in anything that places people in hierarchical boxes. that's my hippie chant of the day.

i'm actually in a good mood today. this is rare.

dc3rd

12:10 AM

well put......must mean you won a case or got a good settlement arranged

leslie townes

we did have a good result the other day. a judge made the other side pay for our fees. and didn't question my time entries either although he did imply that someone else on our team may have been padding the bill.

Ted Shifrin

It's criminal that CORDIC isn't well-known. I passed along misinformation for decades until I got educated about 20 years ago.

leslie townes

that's about when i learned of it.

i'm also happy because a relative who was incapacitated several weeks ago made a lucid post to facebook for the first time since 2017. almost anything mental can be managed but step 1 is acknowledging that there might be a mental thing.

i sometimes blend CORDIC and CRANDIC. CRANDIC meaning Cedar Rapids and Iowa City, a railroad thing. a park near our rented house had this name and was a great place to watch bald eagles in the winter.

they'd fly over a bend in the river and pull fish out.

dc3rd

What was the misinformation Ted?....that trig functions are calculated by power series?.....I ask because a PhD student that was teaching the first real analysis course I took answered my question about "how exactly are trig values calculated" by saying exactly that

It is only here I found out that CORDIC is what is used

leslie townes

the idea that anyone uses power series is a lie, i might even call it the Big Lie, propounded by those with a stake in selling math books.

i can't speak for ted's experience but that was my own.

Ted Shifrin

12:19 AM

Right. I stupidly assumed (having been told by someone ignorant) that it was Taylor series, plus knowing some basic facts.

dc3rd

another one of the beliefs I have coming crashing down.....I thought power series were the end game for all of these estimates

Larry

Are the only closed sets on the topology {∅, X, {a}, {b, c}} are ∅ and X?

leslie townes

i might need to know the complements of the things in that list. what's X?

sierpinski would like a portion of his licensing fee donated to me.

Larry

X is {a,b,c}

leslie townes

the complement of {a} appears to be open.

Larry

12:21 AM

Oh right, so {b,c}, and {a} are both closed and open

leslie townes

sounds reasonable. this topology does not provide a mechanism for separating b from c. but does provide a mechanism separating a from b and or c.

Larry

What would {b,c} be?

leslie townes

its complement is open..

it is also in the topology.

Larry

Oh sorry I meant what is {a,b}

or {c,a}

leslie townes

these sets appear to be neither open nor closed.

Peter John

12:25 AM

@BalarkaSen That is a surjective system isn't it?

Larry

Thank you @les

@leslietownes

leslie townes

i like "les" as a shortening. i may go by that from now on.

Onir

less

Ted Shifrin

12:46 AM

Les is more?

Onir

Les is a Moor?

LSS

1:01 AM

Guys, quick question. The set of polynomials of degree greater than 6 isn't a subvector space of Pn, right? The book i am doing says it is, but i don't see why:

x^6+x^4+(-x^6) = x^4

greater than or equal, over real field

leslie townes

lower bounds on degree will not generally be preserved by vector space operations.

x^n - x^n = 0 seems troublesome. the book might need editing.

Onir

that set doesn't contain the 0 polynomial

if you include the 0 polynomial it is though

leslie townes

you can certainly consider a span of a set of high degree polynomials as a vector space, and this space might not include certain lower degree polynomials, or all polynomials of lower degree.

Onir

oh I was thinking of the one that only had non-zero coefficients of degree > 6

so the one spanned by $x^7,x^8 \dots $

leslie townes

as you noted, a vector space's need to include a zero vector is troublesome here.

Ted Shifrin

1:17 AM

@Onir wrong.

Onir

yeah I was thinking of the one that only had non-zero coefficients of degree > 6

Ted Shifrin

LSS makes a point more important than $0$

Onir

well, when a book says something I tend to believe it

that's my initial response

but yeah, in general in cancelative structures I think closed things cant have closed complements

leslie townes

please buy my book, Invest in LeslieCoin by Leslie Townes. it instructs all readers to put any assets they have into something called "LeslieCoin."

Onir

or something like that

I can't do that but I can shout you out on my tiktok

I only ask 10k If LeslieCoin gains 20k marketcap 24 hours after my post

Ted Shifrin

1:30 AM

I got an irate email from someone telling me that an exercise in Fraleigh's algebra book contradicted a claim (with proof) in my algebra book. Clearly Fraleigh had to be right and I had to be wrong. Oops.

leslie townes

that's funny.

fraleigh was my first introduction to abstract algebra. in hindsight, there are sections of it that i like and sections that i don't.

Ted Shifrin

I don't like his spoonfeeding style, but I liked the eclectic contents in the early editions.

leslie townes

there's stuff in my edition of the book that seems far too dumb. this might be his spoonfeeding style. i liked how he pointed out that counting arguments can be powerful. he failed to leverage this and other proof strategies in his own book.

Ted Shifrin

Yeah, after my book, I choose Artin :)

Very different audiences.

leslie townes

he also puts groups before rings and maybe that is the abstract mathy ordering instead of the teach people stuff ordering.

Ted Shifrin

1:35 AM

That's what 80% of texts do.

You're voting for me, I see.

leslie townes

i hate how much we agree these days.

Ted Shifrin

Oops.

leslie townes

prof. wu is also in our camp on this. rings before groups.

or he was when i last talked to him about this.

Ted Shifrin

I think he may have used my book one time. Hard with Berkeley's course syllabus.

leslie townes

they discontinued 'transition to upper division mathematics' after i taught it twice. i said, just make everybody take discrete math. they'll get proof techniques in there.

they ended up doing that.

a lot of undergrads at berkeley are only interested in teaching high school, which is a laudable goal, but also makes a fraction of these students highly hostile to anything that isn't directed at teaching high school.

Ted Shifrin

1:42 AM

From Jordan Ellenberg: You can’t maintain a dislike for any part of mathematics because all of its branches touch each other.

That’s to you!

leslie townes

that point is well taken. i will stubbornly maintain a dislike for anything i want.

Ted Shifrin

Just like I hate most lawyers.

leslie townes

my daughter is a comedian. "now i'm playing with livvy." livvy is the cat. livvy did not want to play with her. there were annoyed meows.

Ted Shifrin

My kitten would gouge — bite and scratch deeply — your comedian.

leslie townes

lawyers are generally garbage.

myself included in that.

Ted Shifrin

1:47 AM

Granted.

leslie townes

one time we went to a party and later my wife said 'XX was super weird, where do you know him from?" and i had to say, i'm sorry, mathematicians are weird, someone decided to award that guy a seven figure cash prize for something. which is wrong because clearly it should have been awarded to me.

my cat bit my daughter.

my daughter said "i was trying to play with her." she wasn't trying to play with you.

learning when people are trying to play is about 90% of becoming an adult.

Ted Shifrin

My kitten has a long way to go on learning restraint.

Transcript for

$Mathematics$ Mathematics