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Harmonic Function Theory (axler.net)
37 points by ibobev on Aug 8, 2024 | hide | past | favorite | 16 comments


If any of you LLM optimists want a project to try to justify those silicon fires I'd suggest starting with an automated service that converts all of the troves of academic material written in proprietary mathematical source code (mathematica) into open alternatives (sage, python).

See also: https://oeis.org/


Mathics is an open source clone of Mathematica.

https://mathics.org/

Naturally, Wolfram hired the creator and the project nearly died. A couple of heroes stepped in to create a second generation, but it's just too hard to continually compete with a multi-billion dollar company.

No idea how OEIS is involved.


When you use OEIS you find that many sequences have generating source only in Mathematica.


Do you have links to these services & libraries (assuming they can also convert the wolfram binaries?)

Appreciate!


I don't know about this book, but I highly recommend "Linear Algebra Done Right" by the same author. It is a very clear presentation of Linear Algebra. Although I would recommend it for someone who already took a first course on it.


My High School teaches it as the introductory Linear Algebra course and - while it is a bit difficult - it does an excellent job priming students to think about Lin Alg as a higher order discipline.

After doing it both ways, I really appreciate introducing vector spaces and linear transformations before even touching matrices.


May I ask what high school? We did not have a linear algebra course in my New York high school. I would have liked to have been able to take linear algebra then.


Pretty exclusive private bay area school - not the norm by any means. It's offered as one of the electives after calculus - multivariable, linear algebra, and a rotating set of others.


I never really got the hang of Laplacians, which are fundamental to the motivation behind and study of harmonic functions. But here’s a short Khan Academy video I just watched which gives a nice intuitive explanation of the Laplacian operator: https://youtu.be/EW08rD-GFh0


Any book that gives a full pdf preview, I’m at least considering purchasing. I don’t want to take money out of the author’s pocket, but this,

> Printing has been disabled from within this pdf file, so although you can view the entire book, you will not be able to print it.

Yeah, I don’t believe that. The goal of the author is admirable. I feel like they got fooled somehow, but maybe they do understand and are just hinting that if you’re going to read it, kick them some cash.


I think it's like a wink wink


That makes so much sense.


Like how cheap Masterlocks can be overcome by amateurs, even though it's not a real deterrent it "keeps honest people honest"


> Yeah, I don’t believe that.

The PDF format does actually let documents instruct PDF processors to disallow printing [0]; Acrobat Reader (if nothing else) presumably respects these instructions, even though they're obviously possible to work around.

[0] e.g., https://opensource.adobe.com/dc-acrobat-sdk-docs/pdfstandard..., p. 123, Table 3.20, "User access permissions", and probably others that I can't find right now


It's absolutely lovely that you looked up the spec.

First, you could screenshot each page, and print that. That's a lift.

Second, It's not that hard to extract text from pdf file formats. That's also a lift.

but like, it's not that complicated. yes, text flow, font selection, on and on, but it's just postscript. Pull the text and print it. It's signed not encrypted. It's challenging to implement pdf. javascript support is nuts, for example.

But if you just want to pull the text? there's not much to it.

Pay the author. It's not much. But like, it's not locked down.


Awesome book; great reference in grad school.




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