Hermitian Form Puns

I'm working through Artin's Algebra, and while he introduces forms that are not positive definite, I haven't yet seen any examples of where the extra generality is actually used.

I don't want to step on anybody's toes here, but the amount of non-dad jokes here in this subreddit really annoys me. First of all, dad jokes CAN be NSFW, it clearly says so in the sub rules. Secondly, it doesn't automatically make it a dad joke if it's from a conversation between you and your child. Most importantly, the jokes that your CHILDREN tell YOU are not dad jokes. The point of a dad joke is that it's so cheesy only a dad who's trying to be funny would make such a joke. That's it. They are stupid plays on words, lame puns and so on. There has to be a clever pun or wordplay for it to be considered a dad joke.

Again, to all the fellow dads, I apologise if I'm sounding too harsh. But I just needed to get it off my chest.

I am reading descriptions like these regarding observables in QM:

>"The eigenvectors of a von Neumann observable form an orthonormal basis for the Hilbert space, and each possible outcome of that measurement corresponds to one of the vectors comprising the basis."

I have some very basic questions, to gain a more intuitive understanding:

1. If you have an exactly 33-dimensional Hilbert Space, for example, then for any Hermitian operator (corresponding to some observable), there will always be exactly 33 eigenvectors (and they will all be orthogonal to each other)?

2. We care about the 33 orthogonal eigenvectors that get either scaled up or squished down to a length of 1 ("orthonormal"). The eigenvalue of some vector—i.e., the real scaling factor of this vector from before vs. after the operator—is the value of the measurement, if in fact the system ends up collapsing into that state vector?

3. When the measurement is made, is one of these 33 eigenvectors chosen? That is, the system "collapses" into one of these eigenvectors? And the eigenvalue is the actual value of the measurement?

Please let me know if I'm on the right track or wildly off! Thanks in advance!

Do your worst!

I'm surprised it hasn't decade.

Many undergraduate linear algebra classes motivate the introduction of bilinear forms via inner products. Suppose the instructor at the end wanted the students to study alternating bilinear forms and needed some motivation. What could the students be given that would make sense at their level?

For context I'm a Refuse Driver (Garbage man) & today I was on food waste. After I'd tipped I was checking the wagon for any defects when I spotted a lone pea balanced on the lifts.

I said "hey look, an escaPEA"

No one near me but it didn't half make me laugh for a good hour or so!

Edit: I can't believe how much this has blown up. Thank you everyone I've had a blast reading through the replies 😂

It really does, I swear!

They’re on standbi

Buenosdillas

Pilot on me!!

Dad jokes are supposed to be jokes you can tell a kid and they will understand it and find it funny.

This sub is mostly just NSFW puns now.

If it needs a NSFW tag it's not a dad joke. There should just be a NSFW puns subreddit for that.

Edit* I'm not replying any longer and turning off notifications but to all those that say "no one cares", there sure are a lot of you arguing about it. Maybe I'm wrong but you people don't need to be rude about it. If you really don't care, don't comment.

When I got home, they were still there.

What did 0 say to 8 ?

" Nice Belt "

So What did 3 say to 8 ?

" Hey, you two stop making out "

I won't be doing that today!

Nothing, he was gladiator.

[Removed]

You take away their little brooms

This morning, my 4 year old daughter.

Daughter: I'm hungry

Me: nerves building, smile widening

Me: Hi hungry, I'm dad.

She had no idea what was going on but I finally did it.

Thank you all for listening.

There hasn't been a post all year!

Why

I am currently taking the second level Linear Algebra course which has this description:

>Vector spaces. Inner product spaces. Examples of n-space and the space of continuous functions. Gram-Schmidt process, QR factorization of a matrix and least squares. Linear transformations, change of basis, similarity and diagonalization. Orthogonal diagonalization, quadratic forms. Applications in a variety of fields.

And I'm wondering if it would also be worth taking this third course, Linear Algebra III, which has the description:

>Hermitian and unitary matrices, spectral theorem. Jordan canonical form. Cayley-Hamilton Theorem. Bilinear forms, positive-definiteness, Sylvester’s Law of inertia, geometric lattices. Numerical methods. Application to discrete system evolution, matrix exponentials and differential equations.

It's either this or Graph Theory, which would you recommend? Thanks in advance.

It’s pronounced “Noel.”

After all his first name is No-vac

This review consists of two parts: an overview with marked spoilers and unmarked mild thematic spoilers to help potential readers decide if this work is right for them, and a more in-depth analysis, which contains unmarked moderate spoilers for Orthogonal.

#Overview

Tenet: Don't try to understand it, feel it.

Me: Oh come on, Nolan. That's just lazy, now. You call this sci-fi? You know you can't just slap some vague technobabble on it and call it a day, right? I hate how so much science fiction feels the need to dumb it down for the masses. What's the point of hiring renowned physicists to consult on your movies if you end up with scenes where your pilot has to have wormholes explained to him when he's literally in sight of the one he's about to fly through? I wish there was something out there that puts in some actual effort in the worldbuilding, something smart. Something that doesn't treat its audience like idiots. Such a shame, too. Inverted matter looks really cool.

Monkey's paw: *curls*

...

Well, the good news is, I found a story like that. The bad news is, having read it, I now feel like an idiot.

Welcome to the world(s) of Greg Egan, who puts the 'hard' in 'hard science fiction' in more ways than one.^1 He's the author of works such as Permutation City and Sqchild's Ladder, which are considered some of the hardest science fiction novels ever. But while those are set in more-or-less our world, Egan's most valuable contribution to the genre (at least, in my opinion), is his alternate universes, which run on different laws of physics from ours.

Orthogonal is a trilogy of novels (The Clockwork Rocket, The Eternal Flame, & The Arrows of Time; roughly 1100 pages total) set in one such universe. I chose it as my first Egan work to read largely because of its concept, which was just too intriguing for me to resist. From the blurb on the website:^2

>In Yalda’s universe, light has no universal speed and its creation generates energy.

>On Yalda’s world, plants make food by emitting their own light into the dark night sky.

>As a child Yalda witnesses one of a series of strange meteors, the Hurtlers, that are entering the planetary sys

What, then, is Chinese rap?

Edit:

Notable mentions from the comments:

• Spanish/Swedish/Swiss/Serbian hits

• French/Finnish art

• Country/Canadian rap

• Chinese/Country/Canadian rock

• Turkish/Tunisian/Taiwanese rap

There hasn't been a single post this year!

(Happy 2022 from New Zealand)

Nothing, it just waved

Him: I can explain everything!

(It's his best joke yet I think)

Bob

So that I could frequently say, "I am going to walk 5 miles now."

Edit: My most popular post on Reddit! 😀 Thank you for the awards.

Just to clarify, 12345678

Me grabbing a soda from my (what I thought was) half full 12pk...

Notices there's only 2;

Me: "Awe man... This is a damn bird box!" Her: "What the hell does that mean?!" Me: (Pulls both cans out & shows them to her) "It's only got Toucans."

I'm not ashamed to admit the look on her face was glorious.

I was just sitting there doing nothing.