Queue up an answer that includes the phase "that transforms like" closely followed by @DanielSank's scream of horror.

an editing task for someone with spare time

@dmckee Yo.

Finals week here. Grading sucks.

@dmckee I'm tempted to write something about free modules/free vector spaces. It will elicit the same scream.

@dmckee do you ever get people who surprised you with bad grades?

@0celouvskyopoulo7 Not like "I was expecting an A but you gave me a D", but one letter grade happens a lot.

like people you thought would get an A but end up with a B?

@0celouvskyopoulo7 Yeah. Or thought they were getting a B and got a C, or occasionally ones who thought they would squeak by with a D and got an F.

I do enough midterms and stuff for people to be pretty clear on how they are doing. But flub the final or forget to turn in the last three homework assignments and you can drop pretty suddenly.

And my school doesn't do + and - distinctions. So an 88.5% average is a B.

I was sitting on the edge of my seat for my thermo grade

@dmckee At my school it's up to the teachers to decide. I have a stupid A- from a 93 in philosophy.

Which hurts. I remind them that they got a full blown A for that 91% last semester and that sometimes takes the sting out of it.

I put a 'most demanding case' grading scale in my syllabus, but reserve the right to make it easier.

But I haven't felt the need to do that much recently.

I'm getting better and writing assignments and test to match the class's preparation.

It's interesting, I always did crap on midterms and better on finals.

@DanielSank Really? I remember stuff easier for midterms

@DanielSank Most classes were like that for me. But E&M and thermal were the other way 'round.

My buddies and I would do a complete review of the semester over dead-week, and I think that made a big difference in putting stuff in context.

Yeah, midterms were easier material, but I almost always had the same problem:

At the midterm, I was still trying to figure out wtf all the words meant and how everything fit together.

^ Context and big picture needed.

I would be behind the whole semester until the end when I finally understood why all the formulae were how they were.

@dmckee Also professors explaining wtf things mean.

Or, well, usually them not doing that and me eventually figuring it out.

:D

My measure theory final had stuff from the first week of class

I didn't bother to review

Stat mech was a good example.

There were all these partial derivatives and Legendre transforms and I had no f------ clue what it meant.

There were formulae about heat engine efficiency, and entropy and who knows what else.

I think I once understood what a Legendre transform was

It took me all semester to sort it out.

I'm finally beginning to feel comfortable with stat mech this semester...

If you can explain thermodynamics to me, then I'll thank you.

@0celouvskyopoulo7 I wrote a little paper on them for my students this term. That;'s part of why I think I finally get it now.

I know it's all about Legendre transforms, but that's it.

The quantum II midterm was a disaster.

We had learned about Clebsch Gordon or whatever they're called.

@dmckee I did something similar with the eigenvalue problem on a compact manifold. I wrote a really detailed explanation of the whole thing, and by the time I was half done it just clicked and now I get it

Nobody ever just came out sand said "these are the elements of a change of basis matrix".

I may or may not continue writing it

If they'd said that, I would've understood it.

@DanielSank Huh

That's how my prof talked about them...

Then your prof was better than my prof.

You want to put your states in the total $j$ basis and you need to expand in the old one

Why are you explaining it to me?

So it's just the elements of the change of basis matrix

@DanielSank To make sure you know

@0celouvskyopoulo7 Define "total $j$".

This was one of the things that confused me so much.

That's just some phrase, not an operator.

@DanielSank $\mathbf J=\mathbf J_1+\mathbf J_2$

@DanielSank The purpose (well, one of the purposes) is to let you arrange to have the work-like or heat-like (or chemistry-like) energy transfer terms go to zero in your problem.

@0celouvskyopoulo7 What is that?

Why is it bold?

Vector operators

It's the definition of total angular momentum

I can put some tensor products in if you want to be pedantic.

The change in plain-ole energy due to heat is zero for adiabatic processes, which is great until you have to deal with a isothermal process. So think about the change in Helmholtz energy, instead and you get back to have the $T$–$S$ term go away. Yeah.

@Slereah There's a Choquet & Choquet-Bruhat paper.

@0celouvskyopoulo7 I have a large yellow book by them, I think.

Manifolds, Analysis, Physics?

That's by YCB and Cecile Morette-De Witte.

Maybe De Witte-Morette.

god, this paper is using bold and unbold and it's impossible to tell which is which

@0celouvskyopoulo7 What does that mean?

@DanielSank an operator valued element of $\Bbb R^3$

> My teachers asked me which one is heavier - 1 kg of iron ball or 1 kg of cotton ball. I told him iron ball is heavier . But he didn't agreed and told me both have same weight. So I told him to hit me with 1 kg of cotton ball and I will hit him with 1 kg of iron ball . If both weights equal both will hurt equal . My teacher left the job😁😂 -Facebook post

lol

Anyone here?

Hi Kaumudi :)

How's it going/

Societal conventions are a pain eh? I'm okay. What's the matter?

If that's another Rick Roll link ... :-)

@Kaumudi.H Glad it's better now. Coldplay, I see

@Kaumudi.H Yes. You as well?

August? UK universities start in September.

What date does the university year finish?

@Kaumudi.H Oh, all the best with your endeavours! I graduated recently actually. Now onto graduate studies. So you'll be studying physics?

I had that in mind lol

@JohnRennie Mine also used to start in Aug. Aug-Dec. Then Jan-May

@Kaumudi.H But you want to pursue physics or nah?

Ah OK. The year is about the same length but shifted forward a month. In the UK we start in September and finish in June.

yep

@Kaumudi.H Ok. I'm assuming that till now, you've only done high school physics. University physics is quite different, so I would say that you can try exploring some subjects while you're there. There would probably be some electives that are offered to all students, irrespective of what their major is (some basic courses like quantum mech, electromagnetic theory, etc)

But yes, anyway, you should do what you feel the most comfortable with

@Kaumudi.H one pair of jeans and a few T shirts. What other clothes do you need? :-)

Ah, amazing. I have a friend doing research in (somewhat) that. Keep exploring and learning so you automatically gravitate towards your interests and talents.

Neuroscience is pretty interesting. Wish I could get my hands on that too.

lol. I hate shopping so much

YES^

If you like music, you can shop with your earphones in all the time.

haha got it

yes

yo dawgs

yes I did major in physics

and math

ematics

@Avantgarde neuroscience is inte5resting so is AI

and philosophy

I'm very close to the ultimate way of livin

@Kaumudi.H so you'll be studying engineering?

cool

is that computer, civil, mech?

how excitin

Kenshin was talking to himself there for a while

@Kaumudi.H CS?

I'm asking what the acronym stands for.

CS generally means Computer Science in the UK

Does that count as engineering?

Ah, that's another difference from the UK. Here CS would be a separate discipline and you wouldn't study it in the Engineering department.

When you said you were going to study engineering I assumed it would be the usual mechanical or civil engineering.

I suspect there are engineers working in CN - someone has to design the kit they use for studying the brain.

Computer Science is good fun. That's basically what I do these days.

CN?

cognitive neuroscience

oh lol

And if you lose interest in neuroscience there are lots of highly paid jobs in computing :-)

Gosh, teaching beginners C++ is like teaching them firearm safety by handing them loaded guns :-)

What is your personal favorite of open source computational engine as an alternative to mathematica?

@Kaumudi.H C++ has lots of facilities for making your app crash in entertaining and innovative ways. Mostly related to abusing pointers.

Most of the more modern languages go to great lengths to try and avoid these sorts of problems.

@Kaumudi.H Seriously.

I never understood files...

You can get obscure bugs e.g. an app will run in debug mode but not when run outside the debugger.

With simple C++ programs it's not usually a big problem, but I've worked on projects like Kodi where there are millions (literally) of lines of code.

5,174,548 lines and counting

It takes enormous discipline to write apps that big in C++ without memory leaks and crashes due to dereferencing corrupted pointers.

To be fair, most introductory courses don't cover all the nerd-speak. You may simply have never come across the term.

@JohnRennie Or even not even compile outside of debug mode...

@Mithrandir24601 well compile time errors are at least relatively easy to spot and fix

A pointer contains a memory address. Dereferencing is looking at the data at the address contained in the pointer i.e. following the pointer to see what it is pointing at. Pointers get corrupted if they get set to zero or a random number, or if the memory they point to has been freed.

Dereferencing an invalid pointer is probably the number one cause of crashes in apps.

@Kaumudi.H that's fairly standard for C++ :-)

Most modern languages don't use pointers so they're immune from that sort of crash, though they can still crash in other ways ...

@Kaumudi.H At school I played the tuba

I haven't played any instrument since, though I used to sing in an amateur operatic society.

CS sounds good

lots of demand for that now and in the future

but i'm sure other engineering branches also have potential

@Kaumudi.H if you got the best score, what branch would you choose?

what branch is the hardest to get place?

interesting

I think in Australia other engineering branches are harder than CS to get a place

exhausted

y

walked the way home

y

as a step in the proletariat revolution

i don't get it

what a bourgeois

what is proletariat

ru communisit?

y so little sleep Kaumu?

Proletariat is the collective terminology for the working class in the postmodernist capitalist society.

dats no gud

@Kenshin Over here, computer science varies a lot between universities. Some places have it very theoretical with electrical engineering, so that you actually understand what's going on. Others are essentially courses in how to program, yet others focus on things like games development, so how hard the courses are to get into also varies quite a bit

Insomnia is bad.

i slept at 6, woke up at 9

what did u do? just lie in bed awake for hours?

@Mithrandir24601 I see very interesting

r u still studying hard?

oh yeah not long at all

@Kaumu for?

until she leaves physics.SE

I can bet she can't. Any SE site is incredibly addictive.

nah

i have to decide what i want to do

how come Balarka

what level of life r u at

Worldbuilding counterpart to the 3rd Law of Thermodynamics:

over 9000

Clarke's 3rd Law

Any sufficiently analyzed magic is indistinguishable from science

so ur relaly old?

i pretend i am old. i don't really connect to the the young generation, morally physically or intellectually

""young"" ""generation""

so you like to date older ladies?

@Kaumudi.H to be fair, I started of in CS, then ended up in Physics...

Given any worldbuilding setting where both magic and science are present, if the magic cannot violate Clarke's 3rd Law, then strictly speaking that setting has no magic

i don't quite know how to reply to that ...

whether violation of Clarke's 3rd Law is a mathematical impossibility like the 3rd Law of Thermodynamics in the absence of infinite quantities is an open question, however

it's ok no judgement

how old r u tho?

However, it is unknown if Clarke's 3rd Law is actually well defined enough to be put into a mathematical setting so we can prove/disprove the existence of counterexamples

I need to know what pidgeon hole to put you in

One trouble is the highly context sensitive nature of language

ty Kaumu :)

biologically i'm a teenager

yeah I thogut u were older

I thought u were prolly 18

mhm

yeah intellectually i'm like 15

@Kenshin that depends on what you consider the average intelligence of a 15 year old.

I am 22 but I behave like a 12 year old

lol

intellect peaks around mid 20's so basically my intellectwon't peak until mid 30s

I have a suggestion.

That feed is annoying.

$\mathscr{S}$ is the collection of all consistent possibilities and $A$ is one of the possibilities. The maps $K$ indicate the subcollection of possibilities one given possibility can access to

Therefore, a sufficiently advanced technology is expected to have at least one map that has the largest image set

(which means I made a typo, $dom$ should be $img$ )

Clarke's 3rd law basically said that for all such sets that maximise their image set under the maps $K$, the image is equivalent to the set of technologies

Now the issue is, how to define $K$ explicitly

After $K$ is defined, then it will be possible to compute the proof of this problem

Put it in another way, magic is any set $A \in \mathscr{S}$ that does not get mapped to $T$ the set of technologies by all possible mophisms $K$. Clarke's 3rd Law means that $A$ is empty

io9.gizmodo.com/…

The stuff mentioned in the above link is meaningless if Clarke's 3rd Law is mathematically proven

In essence, proving something is a zero sum game, you either win, or the others win. The only case where it is not zero sum is that it is equivalent to the halting problem and hence undecidable

The reason why I construct the zero term algebra investigation some months ago is I want to show whether when they say impossible is really absolute. Impossible is a very strong word, if it is used, to me it often means a mathematical impossibility no matter how witty you are

The idea is that either they are shown to be wrong and they will shut up, or I am shown to be wrong and I will shut up

The goal is the same: When facing any ambiguity, the desire to shut them up tends to one

All unexplained things will eventually be explained, whether by science, by art or (if suitable) by religion

CWV: This world does not tolerate ambiguirities

I don't care who is wrong or right, but given any heated topic that can be solved and the answer is either true or false, one party has to shut up after the statement is shown to be true (or false)

Of course:

Most real world problems are a continuum, and there is no true or false, which makes analysing them more difficult

But bleh, rambles are rambles. Better get back to work

"This article is dedicated to Rafael Sorkin, whose friendship and tutoring from third grade onward is responsible for one of us (JF) having spent his adult life in physics and whose work has inspired both of us."

RIP the SciFi Stack Exchange chat room

Not that we ever discuss contentious things here of course :-)

What? Mos Eisley is gone?

Glad I have not left too many acorns buried in Mos Eisley else it will be a major loss

(Looks like I need to consider digging up all acorns from all SE chatrooms I visited, now that such events is made known to me...)

Guys, shouldn't they have written: $mgy=mg(7\, \mathrm{m})$?

And we’ve defined $E\equiv 1/2mv_0^2$, so how can they say that both $E$ and $V(x)$ are very much negative? Isn’t it that only $V(x)$ is negative?

Or actually.. maybe it should have been: $mgy-mg(7\,\mathrm{m})$

oh oops, I see it now

it is a point 7 meters below the ground, hence $-mg(-7\,\mathrm{m})=+mg(7\,\mathrm{m})$

:D

Still, how can $E$ be negative?