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Iso (math fool)

@isomorphicphi.bsky.social

Background in theoretical physics/mathematics. Interested in mathematics, philosophy and physics. Now I teach. Some kind of anarchist communist, I guess. Swe/Eng.He/they.

158 Followers  |  145 Following  |  136 Posts  |  Joined: 26.07.2023  |  2.1377

Latest posts by isomorphicphi.bsky.social on Bluesky


Whaddup groupoids?

12.11.2025 17:36 โ€” ๐Ÿ‘ 1    ๐Ÿ” 0    ๐Ÿ’ฌ 0    ๐Ÿ“Œ 0

My phaneron has itchiness predicated of it

25.06.2025 19:41 โ€” ๐Ÿ‘ 0    ๐Ÿ” 0    ๐Ÿ’ฌ 0    ๐Ÿ“Œ 0

Abstract nonsense is way easier to understand the sixth time you go through it

25.06.2025 19:39 โ€” ๐Ÿ‘ 2    ๐Ÿ” 0    ๐Ÿ’ฌ 0    ๐Ÿ“Œ 0

She's called an inner product space because she's got a product in 'er

18.06.2025 17:02 โ€” ๐Ÿ‘ 1    ๐Ÿ” 0    ๐Ÿ’ฌ 0    ๐Ÿ“Œ 0

I don't know off the top of my head if anyone writes about this, but it seems to me correct that conspiracy theories are pseudo-paradigms (ie what Kuhn confusingly calls pre-paradigmatic paradigms)

25.03.2025 15:51 โ€” ๐Ÿ‘ 1    ๐Ÿ” 0    ๐Ÿ’ฌ 0    ๐Ÿ“Œ 0

I am back to looking at "geometry stuff", so maybe I should have a look soon

20.03.2025 17:23 โ€” ๐Ÿ‘ 2    ๐Ÿ” 0    ๐Ÿ’ฌ 0    ๐Ÿ“Œ 0

I only have Gauge Theory & Variational Principles by Bleecker. I haven't read it so I don't know if it's good

20.03.2025 15:49 โ€” ๐Ÿ‘ 3    ๐Ÿ” 0    ๐Ÿ’ฌ 1    ๐Ÿ“Œ 0

It's a 'long book is long' problem. It's like the old joke

"I thought the book was longer than it is."

"Well, that's silly. No book is longer than it is!"

Capital is longer than it is.
length(Capital)<length(Capital).
Contradictory? It's dialectics, or something

18.03.2025 08:02 โ€” ๐Ÿ‘ 2    ๐Ÿ” 0    ๐Ÿ’ฌ 0    ๐Ÿ“Œ 0

[In optimistic naรฏvitรฉ:] I should start reading the Marx man again

18.03.2025 07:58 โ€” ๐Ÿ‘ 1    ๐Ÿ” 0    ๐Ÿ’ฌ 1    ๐Ÿ“Œ 0
Post image

Dear boooks, please provide insight

11.03.2025 18:25 โ€” ๐Ÿ‘ 2    ๐Ÿ” 0    ๐Ÿ’ฌ 0    ๐Ÿ“Œ 0

There is some metric isotropy group of the bundle too, right?

I literally just reprinted the notes from my course in the way back

11.03.2025 18:16 โ€” ๐Ÿ‘ 1    ๐Ÿ” 0    ๐Ÿ’ฌ 2    ๐Ÿ“Œ 0

Right, so that's very infinite dimensional

11.03.2025 17:55 โ€” ๐Ÿ‘ 1    ๐Ÿ” 0    ๐Ÿ’ฌ 1    ๐Ÿ“Œ 0

Quasi-finitist going, in desperation, "something is finite, right?"

11.03.2025 17:17 โ€” ๐Ÿ‘ 0    ๐Ÿ” 0    ๐Ÿ’ฌ 1    ๐Ÿ“Œ 0

Yeah, I think so too. Really need to brush up on DG. But something is finite dimensional, though. Is it the Lie group of some bundle? Because local Poincarรฉ is the maximal dimension of... something, right?

11.03.2025 17:13 โ€” ๐Ÿ‘ 1    ๐Ÿ” 0    ๐Ÿ’ฌ 2    ๐Ÿ“Œ 0

Now I'm confused, Roch. Isn't the diffeomorphism group the diffeomorphism group of a manifold M (ie a 'solution' to the field eq) while the equations of motion have general covariance? Like that the dimension of Diff(M) is smaller than the 10 dimensions of local Poincarรฉ?

11.03.2025 16:01 โ€” ๐Ÿ‘ 1    ๐Ÿ” 0    ๐Ÿ’ฌ 1    ๐Ÿ“Œ 0

Yeah, I'm always highly suspicious of probability arguments where you measure over potential cosmologies like that (because of the measure problem). I was thinking just mathematically that there is no reason every symmetry of the dynamics should manifest itself in the solutions

11.03.2025 15:26 โ€” ๐Ÿ‘ 1    ๐Ÿ” 0    ๐Ÿ’ฌ 0    ๐Ÿ“Œ 0

Could you elaborate what you mean?

11.03.2025 13:44 โ€” ๐Ÿ‘ 0    ๐Ÿ” 0    ๐Ÿ’ฌ 1    ๐Ÿ“Œ 0

Isn't it exactly the same? A solution to the equations of motion has "fewer" symmetries than the equations of motion

11.03.2025 11:35 โ€” ๐Ÿ‘ 2    ๐Ÿ” 0    ๐Ÿ’ฌ 1    ๐Ÿ“Œ 0

In a sense, I find this no more strange than this claim
"Newton's law of gravitation is rotation invariant, but the elliptical orbit has a prefered plane"

11.03.2025 06:46 โ€” ๐Ÿ‘ 2    ๐Ÿ” 0    ๐Ÿ’ฌ 1    ๐Ÿ“Œ 0

Ignorance is bliss; as David Bizarro-Hilbert once said:
"We cannot know; we must not know"

11.03.2025 06:41 โ€” ๐Ÿ‘ 1    ๐Ÿ” 0    ๐Ÿ’ฌ 0    ๐Ÿ“Œ 0

Frege is OK. Decent philosopher

10.03.2025 20:16 โ€” ๐Ÿ‘ 2    ๐Ÿ” 0    ๐Ÿ’ฌ 0    ๐Ÿ“Œ 0

I'm gonna go for the troll answer, since I in reality basically agree with you:

For any x fitting a definite description, any y distinct from x fails to meet that description

10.03.2025 18:41 โ€” ๐Ÿ‘ 2    ๐Ÿ” 0    ๐Ÿ’ฌ 0    ๐Ÿ“Œ 0

Right, that too

10.03.2025 17:42 โ€” ๐Ÿ‘ 1    ๐Ÿ” 0    ๐Ÿ’ฌ 0    ๐Ÿ“Œ 0

I don't have the dates, but Peirce may have beaten Frege to it. Certainly, it was not an idea unique to Frege at the time

10.03.2025 17:39 โ€” ๐Ÿ‘ 1    ๐Ÿ” 0    ๐Ÿ’ฌ 0    ๐Ÿ“Œ 0

I agree with much of this. "Something" "happened" to mathematics in the middle of the 19th century. One of my favorite throwaway lines from Kuhn is that this something happened at very different rates in different places

10.03.2025 16:53 โ€” ๐Ÿ‘ 1    ๐Ÿ” 0    ๐Ÿ’ฌ 0    ๐Ÿ“Œ 0

I have very large sympathies with this view (probably with some very post-Kantian philosophy of mind/intension tacked on)

10.03.2025 16:34 โ€” ๐Ÿ‘ 2    ๐Ÿ” 0    ๐Ÿ’ฌ 1    ๐Ÿ“Œ 0

But, like, in Kant's defence, viewing mathematics as analytic splits what Kant thought to be mathematics into eg the analytic theory of the Dedekind-Peano-(Peirce) axioms and the empirical theory of its utility in counting

10.03.2025 16:32 โ€” ๐Ÿ‘ 1    ๐Ÿ” 0    ๐Ÿ’ฌ 0    ๐Ÿ“Œ 0

Missing as in failing to realize, rather than failing to consider. But Peirce has the great benefit of being later than Gauss-Bolyai, Boole-DeMorgan as well as Hamilton and his dad

10.03.2025 16:30 โ€” ๐Ÿ‘ 1    ๐Ÿ” 0    ๐Ÿ’ฌ 2    ๐Ÿ“Œ 0

Peirce, who in many ways is a Kantian, critized him for "missing" that mathematics is analytic rather that synthetic

10.03.2025 16:20 โ€” ๐Ÿ‘ 1    ๐Ÿ” 0    ๐Ÿ’ฌ 2    ๐Ÿ“Œ 0

My favorite kind of sheaf is the mist-sheaf

02.01.2025 08:17 โ€” ๐Ÿ‘ 1    ๐Ÿ” 0    ๐Ÿ’ฌ 0    ๐Ÿ“Œ 0

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