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julesh, to random
@julesh@mathstodon.xyz avatar

Me and @zanzi are on our way to EMF (very slowly, because a train derailed near Carlisle)

Do we know anyone on here who's going?

christianp,
@christianp@mathstodon.xyz avatar

@julesh @zanzi I don't know if you know them, but @stecks and @mscroggs are there doing maths things

julesh,
@julesh@mathstodon.xyz avatar

@christianp @zanzi @stecks @mscroggs Last time @mscroggs and me saw each other was in 2011, pretty sure

We'll definitely roll up in the maths tent at some point and say hi

julesh, to random
@julesh@mathstodon.xyz avatar

Vaguely get the feeling that (multivariate) Gaussians are like the linear functions of probability

In which case the central limit theorem kinda looks like differentiation as in the best linear approximation

Is this a thing?

johncarlosbaez,
@johncarlosbaez@mathstodon.xyz avatar

@dougmerritt @julesh - in 1d there are lots of functions preserved by the Fourier transform. There's an othonormal basis of functions ψₙ equal to a specific Gaussian times the nth Hermite polynomial. These are called 'energy eigenstates of the harmonic oscillator'. To take the Fourier transform of ψₙ you just multiply it by 𝑖ⁿ. So every fourth one is preserved by the Fourier transform, and taking linear combinations you get all functions preserved by the Fourier transform.

Something similar works in higher dimensions too.

dougmerritt,
@dougmerritt@mathstodon.xyz avatar

@johncarlosbaez @julesh
Thanks for that. Apparently I latched onto some circumstance in approximation theory and misremembered it as a universal; I'll have to backtrack on those memories.

julesh, to random
@julesh@mathstodon.xyz avatar

This is a hell of an opening line for a textbook

https://www.schneier.com/books/applied-cryptography-2preface/

julesh, to random
@julesh@mathstodon.xyz avatar

A sort of compromise I can imagine for the economics of the tech industry is to add a new exit strategy for startup investors where they sell to the state, the company becomes a public corporation and loses its profit motive. The bar for this would naturally be incredibly high, this is for obviously-infrastructure things like Google Search and Twitter

julesh, to random
@julesh@mathstodon.xyz avatar

Old people, not content with merely destroying the economy for young people, are now trying to actively murder young people

image/png

julesh,
@julesh@mathstodon.xyz avatar

Note that conscription in the UK ended in 1960, because of how many conscripts died in the Korean War. So you would have to be at least 83 years old to have experienced conscription. I will happily listen to the opinion of any politician who is older than 83 on this point since they are speaking from experience, any politician younger than 83 can fuck off and go to hell

julesh,
@julesh@mathstodon.xyz avatar

You might think they were preparing for a war with Russia, where a conscript army would definitely be very useful for defending the varpourised radioactive crater where the UK used to be. But as far as I can tell they haven't actually said anything about Russia, the rhetoric around it is entirely about attacking young people

julesh, to random
@julesh@mathstodon.xyz avatar

I just had an epiphany. The purpose of an review rebuttal is not to convince the reviewers to change their mind - which is obviously not possible except in vanishingly rare cases - it's to convince the programme committee that the reviewers don't know what they're talking about

ProfKinyon,
@ProfKinyon@mathstodon.xyz avatar

@julesh Or in the journal submission case, to convince the editor to ignore the reviewer's recommendation.

johncarlosbaez, (edited )
@johncarlosbaez@mathstodon.xyz avatar

@ProfKinyon @julesh "The purpose of an review rebuttal is not to convince the reviewers to change their mind - which is obviously not possible except in vanishingly rare cases - it's to convince the programme committee that the reviewers don't know what they're talking about."

Yes, and this is also the right attitude when arguing with jerks on the internet. You are really talking to the smarter people quietly looking on.

julesh, to random
@julesh@mathstodon.xyz avatar

Sample a 2d Gaussian with random covariance matrix

julesh, to random
@julesh@mathstodon.xyz avatar

It's not just imagination, Englandandwales really is a conservative religious country compared to Scotland

bhaugen,
@bhaugen@social.coop avatar

@johncarlosbaez @julesh
Can I move to Scotland?

johncarlosbaez,
@johncarlosbaez@mathstodon.xyz avatar

@bhaugen @julesh - unfortunately the British are still effectively in charge of visas.

julesh, to random
@julesh@mathstodon.xyz avatar

I need my students to understand that to get away with openly committing blatant plagiarism you have to be a billion dollar megacorporation, which they are not

julesh, to random
@julesh@mathstodon.xyz avatar

Obviously not everything can be understood with just category theory, although I'm starting to kinda suspect that everything can be understood with a mixture of category theory and statistical physics

boarders,
@boarders@mathstodon.xyz avatar

@julesh statics + dynamics

BartoszMilewski,
@BartoszMilewski@mathstodon.xyz avatar

@julesh I think category theory defines what can be understood because "understanding" is the ability to decompose.

I also believe that not everything can be understood (in fact, things that can be understood have measure zero).

julesh, to random
@julesh@mathstodon.xyz avatar

I'm a city kid and I've never seen any astronomy before... but the northern lights were so bright we could see them in central Glasgow

johncarlosbaez,
@johncarlosbaez@mathstodon.xyz avatar

@julesh - I failed to look out our north-facing windows in Edinburgh. 😿

julesh, to random
@julesh@mathstodon.xyz avatar

Beware the pipeline

image/jpeg

SvenGeier, (edited )
@SvenGeier@mathstodon.xyz avatar

@julesh
Wait, you have to go through a pipeline? I fear we completely skipped that part...

julesh, to random
@julesh@mathstodon.xyz avatar

Please can somebody inform MS Word that the accusative form of "who" is "who" in modern English, it's not 1924 anymore and I'm not writing in German

julesh,
@julesh@mathstodon.xyz avatar

@jer_gib @julesh I'm sticking with this one. If you listen to how people speak, including people of your generation and older and even in Oxford, you basically never hear “whom" in accusative position. Imagine somebody actually saying “I don't know whom you're talking about” out loud, it sounds incredibly jarring to me. I reckon the only version anybody at all actually uses consistently is following a preposition "to”, as though English had a dative case... and it's not 1024 any more

boarders,
@boarders@mathstodon.xyz avatar

@julesh @jer_gib also why stop here? why not use ‘thou’ and ‘thee’ if we don’t care about language as speakers actually speak it, but merely about pretending modern English is Latin

julesh, to random
@julesh@mathstodon.xyz avatar

Someone should write "mathematics for the working category theorist", to teach a bit of algebraic topology to those of us who started out in functional programming

brokenix,
@brokenix@emacs.ch avatar

@boarders @julesh is this a book/paper ? Details?

boarders,
@boarders@mathstodon.xyz avatar

@brokenix @julesh use a search engine

julesh, to random
@julesh@mathstodon.xyz avatar

When you're an overworked academic but you also get to travel to conferences in exotic locations

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