Interactive Linear Algebra Dan Margalit, Joseph Rabinoff • Hacker News Board

Re: Interactive Linear Algebra Dan Margalit, Joseph Rabinoff

#11

Post by lupire » Mon, Sep 02, 2024, 3:18 PM UTC

rtpg wrote: post #5

Looking at the determinant section... I am so glad I got to learn linear algebra separate from matrices because oof this is hard to grok for me. Real "makes esnse if you already know the thing" stuff. But interesting to see that form of determinant definition! https://textbooks.math.gatech.edu/ila/determinants-definitio...

The mathematical pedagogical design isn't bad. But the presentation is terrible -- out of order (linking to sections ahead for explanation), and written awkwardly with minor technical errors (like multiplying by 0) that show the author doesn't fully understand what they are saying or how to express it. They are using stilted English as an attempt at formal mathematical writing.

Re: Interactive Linear Algebra Dan Margalit, Joseph Rabinoff

#12

Post by lupire » Mon, Sep 02, 2024, 3:22 PM UTC

fn-mote wrote: post #6

rtpg wrote: post #5

Looking at the determinant section... I am so glad I got to learn linear algebra separate from matrices because oof this is hard to grok for me. Real "makes esnse if you already know the thing" stuff. But interesting to see that form of determinant definition! https://textbooks.math.gatech.edu/ila/determinants-definitio...

Agreed - it's like they transplanted the "found in a rigorous math class" definition of a determinant. That's the one where the desired properties are the assumption and then you show that your preferred mechanical method of computation gives those properties. Usually there's a final step where you show the properties are enough to establish uniquemess. None of those mathy steps occur in this book. There are just sta…

That's an absolutely terrible goal!

How can you expect someone to learn exactly what you present? No motivation for extension. No context for understanding.

It's supposed to be a textbook, not an exam crib sheet.

The book was meh, but seeing that stated goal frastically lowers my respect for the GA Tech math department. It shows the clear disdain that the professor has for the students and the material they are teaching.

Re: Interactive Linear Algebra Dan Margalit, Joseph Rabinoff

#13

Post by lupire » Mon, Sep 02, 2024, 3:44 PM UTC

lanstin wrote: post #8

0cf8612b2e1e wrote: post #7

Earlier quoted context omitted.

Something that drives me up the wall is just how sloppy math notation can be. Supposedly this pure discipline, but many authors use custom conventions all over the place, shorthand, skip steps, etc. Give me some math code, where the end result has to compile. No sneaky tricks allowed.

You want mathlib, the lean library of established results: https://github.com/leanprover-community/mathlib4 They skip steps in writing because they can generally do them and it obscures the flow of the argument to have every thing spelled out. There is also a book on mechanics by the authors of SICP: https://mitpress.mit.edu/9780262028967/structure-and-interpr...

Lean doesn't have expressiveness notation. It's like Perl line noise.

Re: Interactive Linear Algebra Dan Margalit, Joseph Rabinoff

#14

Post by AlexCornila » Tue, Sep 03, 2024, 3:33 AM UTC

lupire wrote: post #12

fn-mote wrote: post #6

Earlier quoted context omitted.

Agreed - it's like they transplanted the "found in a rigorous math class" definition of a determinant. That's the one where the desired properties are the assumption and then you show that your preferred mechanical method of computation gives those properties. Usually there's a final step where you show the properties are enough to establish uniquemess. None of those mathy steps occur in this book. There are just sta…

That's an absolutely terrible goal! How can you expect someone to learn exactly what you present? No motivation for extension. No context for understanding. It's supposed to be a textbook, not an exam crib sheet. The book was meh, but seeing that stated goal frastically lowers my respect for the GA Tech math department. It shows the clear disdain that the professor has for the students and the material they are teach…

I went there for undergrad and trust me it’s the hunger games. I remember for one class, DSP we would have labs before they would actually teach the material and as a student you were how the Fck can I achieve whatever the lab is asking with the knowledge we learned so far… you couldn’t and it would take a couple of labs to realize that material req was from next class.