(in any case, I could be wrong - I don't know much about active work on tqfts)

is it generally accepted to refer to a line's y-intercept as a fraction like -1/3 rather than -0.333... ?

@Ted: that post office apparently, within the past month, stopped accepting passport applications. they directed me to the airport's passport application center, which is only open on tuesdays. what a waste of a morning :(

oh, ugh, @Mike. I'm sorry.

You'd think they'd put up warnings about that ...

You're making me worried about when mine expires. If I didn't throw it out while I was throwing out most of my house ...

hopefully I can do the app at the airport without too much pain, get out and only lose two mornings, not a morning and a day

also does any one know free software that allows me to generate line graphs which i can then import to microsoft word?

I've got the paperwork, picture, etc, it should just be a manner of handing it in

aha ... I have until next March. Guess I'll have to deal with this once I have a CA address.

Don't forget cash, @Mike.

surely they'll take card

Don't be so sure, @Mike.

thanks for the warning. will bring cash to be safe.

@Dave: This is not my expertise at all. Excel will draw graphs, and I assume you can export, since it's all Microsoft.

im looking for this kind of graph

i don't see an option for that type of graph in excel only data plotting

Holy cow, @Mike. Now passports are $99 + $170 to the Department of State.

lots of websites have them like wolfram but don't really want to import a screen grab =/

Oh, I draw that stuff in Mathematica all the time, @Dave, and then export to things like LaTeX as .eps files. I don't know what Word takes. I abhor Word.

You can also save as .png and .pdf, etc.

is it easy to use

No, it's detestable to use.

:(

Oh, I meant Word. What did you mean? :P

lol !

mathematica

@Ted should not be that much

Mathematica is quite easy, once you learn the basics.

i guess if i can import as png itll be sufficient

@Dave I can't think of many situations where decimals are preferred over fractions, so personally, I would always use fractions. But I guess it doesn't really matter. For me fractions are easier to read and manipulate than decimals, plus they are exact.

I am looking online, @Mike. Yikes. I guess this is all thanks to Homeland Security ...

@Ted I see 110

@DiscipleofBarney the only reason i asked, is because i had to check a point on the graph (its y position) matched my answer. Given its position was 4 and my answer was -0.3...

so wasn't sure if -0.3 was better for consistancy of comparison over saying -1/3 does not match 4

I can afford 110... 269 is a bit much

I'm looking under Passport Renewal, @Mike. My realtor is here, so I'll bbiab.

OK

oh, maybe what I found is a business, not the government, @Mike. I'll have to look more carefully.

Yeah, darn google.

well, talk later

They say to do it by mail they take personal check or money order.

right, but I can't - age req

Right, I saw that.

sounds like the person at the post office suggested I go to the passport center but that's for expedited requests, not regular ones

@Dave Are you saying you got -.333... for your position but -1/3 is not your position?

i was given a position of -6,4 to check with my equation to see if it lies on the line. It didn't because when using the x point i got a different value for y. so i concluded -1/3 is not equal to 4 thus the point does not lie on my line

So i wrote: y = -1/3 does not equal 4, thus the point does not lie on the line. I just didn't like comparing a whole number to a fraction like that

ah, no, my mistake - there's both a passport agency and a regular passport acceptance location at the airport

@Dave Not sure why you don't like it, but fractions are okay, I prefer them.

Well for example.

looks more consistent

Normally you write things for readability and understandability, not consistency.

Plus if you wrote 0.333... then you would "have to for consistency" write 04.000...

@Mike: What's with passport book & card? I have just the book. That appears to be $135.

Card is only for land crossings, @Ted, and then I think you can only use it for travel US <-> Mexico or Canada - not further. Don't bother with it.

(ie you cant go US -> Mexico -> wherever)

Why would someone get both passport and card?

no clue

@Ted: Google seems to say it's convenient when you do land or sea trips - no talking to a border agent, basically just swipe it into a machine. I guess people who travel a lot by sea and get easily annoyed by human contact would benefit from it.

Ah ... so much I don't know :P

@Dave Pro tip: don't ever write 4/1.

well, there's also a lot that's not worth knowing

@AntonioVargas why

Unless it's a date.

@Dave Because it makes it look like you don't know what you're doing.

don't see how

People who know what they're doing simplify fractions. That's how. It's a cultural stylistic choice.

It's like writing sqrt(1) instead of 1

What if i simply say "4 can be expressed as a fraction for our calculation as 4/1" then do the calculation all fractions

for example: y = -3/4 * 4/1 + -3/2

Are you writing for an audience who wouldn't understand that without you telling them?

also I would advise you to add some parentheses to that expression; it's ambiguous.

no but i just like to write my workings fully expressed etc

wheres the ambiguous part?

in the common order of operations, division and multiplication have the same precedence, and are evaluated from left to right when they appear next to each other.

well yeah but i don't know how to format so they look like fractions in a browser

rather than seen as division

(-3/4)*(4/1)

oh okay

my document has my fractions written using proper formatting

ah k

so won't need brackets there

kinda wish browsers natively supported math formatting

anyway, good luck on getting your workings fully expressed, you're chasing a dragon ;)

They do; look at " $\LaTeX$ in chat " on the right

Look at the $\LaTeX$ in chat @Dave

thats not native thats a plugin

You just click on the bookmark and it gets pages to output the math.

yes but also as a computer programmer etc i can't write variables over variables

i have to use /

as a computer programmer, I don't have a problem writing $\frac{1}{4}$ to mean 1/4

i guess brackets help but still

bit ugly

@AntonioVargas isn't the upright version preferable? (sorry, coming into the convo late)

@Dave Dave, try using something like Maple, or Mathmatica. they are pgming langs that accept math notations

@Jeff It depends for me. I use \frac in displayed equations outside of exponents and use 1/4 inline and in exponents.

i much prefer \frac over \nicefrac

$\nicefrac{1}{4}$

Hm I guess they don't have it here

What is nicefrac? Haven't heard of it

Oh I see, that's kinda nice. i.stack.imgur.com/C47M5.png

@AntonioVargas you have to use the nicefrac package. works identical to /frac, but you will probably prefer nicefrac for inline math

Thanks, I'll give it a shot :)

@BalarkaSen @MikeMiller I was looking around at the TQFT and it looks like there was a mini-course that was recorded, plus some notes that went along with it: here is the link to the page

thanks for the link

most everything there looks reading, not just segal's qft / lurie's tqft courses

Not sure if you have seen it, but Cornell has a good amount of topology/geometry videos from a couple of conferences they held

here is the link to the relevant Cornell

I do

I prefer notes to video because I tend to appreciate lectures partially by the notes I took and read afterwards

some great talks on that page though nonetheless

i have seen some of them but not all. thanks, @DiscipleofBarney

huh, for some reason, i find that i like to watch curt mcmullen's lectures.

one of the reason might be that his lectures are most often on hyperbolic geometry. his talks are pretty well-polished.

@BalarkaSen I just went to his wiki and they give about as much time to his work that he won the fields medal for as to his proof that backgammon games end with probability 1! hahaha I will have to take a look at some of his lectures though

You can do worse than watching lectures of Fields medal winners, @Balarka :)

@Ted just between ourselves, my prof doesn't think he's as great as everybody claims (and mcmullen was his co-advisor). for one, he even wrote an article on how to win a fields medal :p

he's an analyst, more like. not much of a hyperbolic geometer.

Well, I don't know him personally. Well, there are lots and lots of analysts doing geometry. Geometry has changed, a lot to do with Yau, since the 70's.

fair.

Anyhow, wait until you're double your age to have cynical opinions :P

:p

agreed.

By then, I'll be dead :D

too bad. or maybe it'd be "too good" for you.

We'll see how it goes. I doubt I'll have a say.

yeah, i am not even sure if i will study math.

oh, the thought of your not doing math is preposterous.

i'll do math alright. i'm just worried that i'll fail in my high-school graduation :p

Well, see to it that you don't.

well, first he has to stop having negative reactions towards every field he hasn't actively studied

but I suspect he'll have done that by the time he reaches... oh, 16

Well, @Mike, his behavio(u)r has mollified greatly in the past year or so ... Our yelling/ignoring has had its effects.

Plenty of our grad students/faculty are just as narrow-minded.

well, I didn't know what analysis was when I was 16, so I think it's great progress

i just "know" what analysis is. i didn't really study any of it, remember?

:p

I didn't learn any algebraic topology until I was 21.

I guess I beat you by a year, @Ted

Nor any differential geometry until I was 21, although I learned Guillemin & Pollack when I was 19, I guess.

It's too far back for me to count.

Me too, @Ted

that every commutative frobenius algebra is a 2-dimensional TQFT is a cool fact.

yeah, you're old to the bones, @Mike.

@Mike, if you can't count backwards to 2, we're in real trouble, unless you do all your topology mod 2.

@Ted: I mentioned in a talk recently that the biggest number I was going to use was 2, which was convenient, because I can't count higher than 4 or 5.

haha

@MikeMiller TQFTs seem to get harder to calculate as the dimension increases. is it really an "easy" invariant, or just a good one?

No, they're not easy invariants. Easy invariants are generally worthless.

not true. counterexample : singular homology.

Stop being so cheeky.

well, singular homology really is an easy-to-compute invariant. it's useful too, if you don't count returning Z for all knot complements.

i'll desist. i guess i need to sleep too.

@Balarka: I think it was perfectly clear what I meant. Of course singular homology is fairly easy to compute, given a cell decomposition. They are decent for telling apart some homotopy types. If you want to do something more interesting, like tell apart homeomorphism types, or even better diffeomorphism types, you need to work harder. The most common TQFTs (or at least, things that look like TQFTs) are built to do the latter.

Study complex structures, instead ... Much more difficult.

Sure. If you want to do geometry at all, you need to work harder yet. Though again these same sorts of invariants show up (Heegaard Floer homology is valuable for classifying contact structures on 3-folds...)

@Ted: isn't the moduli space of complex structures on a smooth mfld infinite dimensional for surfaces and above? seems like there shouldn't be any form of reasonable classification

won't let me delete two back. shame

I don't think that's right. Different K3 surfaces are given by a finite-dimensional variety (and I used to know the dimension).

interesting

I haven't quite forgotten more than I once knew ... but I may be getting there asymptotically.

would offset be the right word?

@Dave "constant term" or "y-intercept"

I guess "vertical offset" would also be technically correct, though not common

@AntonioVargas ok thanks

damn it i wrote all that and not got the answer i was expecting

@TedShifrin That is really sad to read

How are you @Disc?

I am good, how about you? @Incurrence

@DiscipleofBarney Pretty good. I have caught up on sleep, and now I actually have some time before any of my assessment is due

I have 8 days for Algebra, 14 days or something for Functional

Nice. I caught up on some sleep too

can some one check my workings to see where i have gone wrong

if you have time :)

Offsets what? @Dave

two seconds let me just neaten it up

my offset for my line is way off

so i have obviously got c incorrect

(a/b) - (c/d) is not (a-c)/(b-d)

huh

say I want to subtract 1/3 from 4

okay

by your method I could write (4/1) - (1/3) = 3/(-2)

does that seem right?

ok no it doesn't

you have to find a common denominator first

before you subtract

thats bit tricky with the numbers

unless theres a clever way to identify a common denominator from looking at them

well you multiply 3.4841/1 by 0.1841/0.1841

isn't that simply 3.4841/1 * 1

yeah

the goal isn't to change the number

it's to make it have the same denominator as the other thing

@DiscipleofBarney Do you know much about tensor products?

no

isn't that the same idea

use the numbers I wrote

yes i know

i just meant because 1 is same as 1/1 thus same denominator

you end up with (3.4841*0.1841)/0.1841

and THEN subtract the numerators

since they have the same denominator

hi, @Incurrence ... Didn't mean to make you sad ... yet :P

Not much, a small bit, I imagine the tensor products for groups is more complicated

@TedShifrin Hey Ted, do you use Tensor products in differential geometry much?

yes, tensor products are all over differential and algebraic geometry

Yes you do

(and algebraic number theory)

What is their purpose?

I mean, how do I motivate learning them?

Not for me, but I have to do a 5 min presentation and I think that would be a good starting point