Returning to typefully after a while. Posting this from Raycast -- in general nice to see many new integrations, including Claude and a MCP server.

We want to evaluate $$ \sum_{\color{red}k=0}^\infty (\color{red}k+1) \color{blue}p^{\color{red}k}\,. $$ Introduce the function $f$, for $|\color{blue}x|<1$: $$ f(\color{blue}x) = \sum_{\color{red}k=0}^\infty \color{blue}x^{\color{red}k}\,. $$ That's a nice geometric series, and we easily get $f(\color{blue}x) = \frac{1}{1-\color{blue}x}$. So we can differentiate that: $$ f'(\color{blue}x) = \frac{1}{(1-\color{blue}x)^2} $$ But $f$ was defined as a power series, and we can also differentiate *that* termwise: $$ f'(\color{blue}x) = \sum_{\color{red}k=1}^\infty \color{red}k \color{blue}x^{\color{red}{k-1}} = \sum_{\color{red}k=0}^\infty {(\color{red}k+1)} \color{blue}x^{\color{red}{k}}\,. $$ Well, $f'(\color{blue}x)= f'(\color{blue}x)$ (!), so we can use both expressions, and evaluate them at $\color{blue}p$: $$ \boxed{\sum_{\color{red}k=0}^\infty {(\color{red}k+1)} \color{blue}p^{\color{red}{k}} = \frac{1}{(1-\color{blue}p)^2}} $$

Let's say you want, e.g., to compute the expectation of a Geometric r.v. That'll involve, at some point, evaluating a series of the form "Σ (k+1) p^k" which looks like what Lovecraft may have done to a geometric series. How to do it?

One trick I enjoy: differentiate the same function, in two ways!

I've finally put together the blog post accompanying a lecture that @neeldhara.bsky.social invited me to give over a year ago - which happened about a year after @shriram.bsky.social got us to start thinking about it :)

Eventual consistency, I guess. :)

johnazariah.github.io/2026/02/08/o...

Has anyone tried using Claude or its ilk with Overleaf? I'm tempted to try claude for chrome with OL.

I use claude code in Cursor's terminal which seems to work well for my own stuff. But OL sync with GH or DB is a bit finicky so was wondering...

In the light of the recent news from IISc about tracking time-at-labs, timely to check out this compilation of opinions from the international scientific community on the matter, in the context of a similar situation that arose in Italy:

www.openaccessrepository.it/records/1433...

I figure there may not be any off-the-shelf scripts that I can use. I tried vibe coding, but the part about getting the image recognition to work seemed non-trivial. Have you tried something like this before?

I want a gradescope-like UI for identifying the answer regions and for the app to compute scores of individual students + stats. The reason I can't use GS for my situation is that GS doesn't support confidence-based grading, which is what I am using for this exam.

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How hard is it to create a bespoke gradescope-ish app for a particular pen and paper exam? My use-case is the following: I have a question paper that is all multi-select or short answer (fill in the blanks), and a bunch of scans from an exam that happened.

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Clocked ten years at IITGN today :) Thinking of writing a retrospective of sorts, if you have any ideas for what you might find useful in such a reflection, let me know!

GIAN – Global Initiative of Academic Networks Official portal of GIAN, a Government of India initiative hosted by IIT Hyderabad to enable international academic collaboration.

Having done this a couple of times (imperfectly), happy to help any way I can! Happily, the documentation covers a lot of ground already:

gian.iith.ac.in/guidelines

(2/2)

ICYMI: a new phase of GIAN funding has been announced. If you are an eligible faculty member in India, great opportunity to play host, and if you identify as a "foreign expert" who'd like to visit, ping your friends here!

Deadline: Sep 30. (1/2)

TIL that Pocket shut down :( Was my first read-it-later app. I haven't used it in ages, but still feel like I'll be missing it! I remember setting up IFTTT workflows to spam people when I tagged them on a pocket entry 😀

I am likely to be very off in my estimates of how long the chapters will take, but we'll figure it out as we go along :) Logistics: the readings will be coordinated via Circle (as an experiment) instead of WA groups. Please make sure to sign up at the links on the GAB site.

The Theory of Probability | Santosh S. Venkatesh, Professor From its classical foundations to the advanced modern theory, this elegant guide to probability weaves together mathematical proofs, historical panoramas, and lush, richly detailed applications.

In the mornings IST, we are reading Theory of Probability.
Book website: www.santoshvenkatesh.com/book
GAB site: grokabook.com/texts/2025/p...

In the mornings IST, we are reading DCIC
Book website: dcic-world.org/2025-02-09/i...
GAB site: grokabook.com/texts/2025/d...

The Theory of Probability | Santosh S. Venkatesh, Professor From its classical foundations to the advanced modern theory, this elegant guide to probability weaves together mathematical proofs, historical panoramas, and lush, richly detailed applications.

Happy to announce new editions of grok-a-book this term! We start effectively on the 8th of September (with a meet-and-greet type meetup on the 5th). Details in thread.

Recently vibecoded some slides in Manim via manim-slides:
slides.neeldhara.com/evc/

The whole experience was... interesting. It's not replacing my current default for now, but might find ways of integrating it in modular ways.

Slightly niche question: does anyone have Obsidian web clipper working on the Orion browser?

A page from Edward Lasker's chess book.

Now I can give you a more complete reply, @neeldhara.bsky.social. The chess book I was thinking of is Chess: The Complete Self-Tutor by Edward Lasker. Here is a sample of the interactive style.

Chapter categories

Table of contents

The closest thing for me as a young person learning about computer science was ‘The Turing Omnibus’ with its bite-sized chapters and categories. My memory is chapters would tell you what was next so you could follow the automata or cryptography ‘paths’.
I only have the ‘new’ version.

Do you know of any examples of textbooks written in the style of interactive fiction?

TIL that Screenflow can’t import a MOV file generated by OBS studio :(

Anyone using the OBSBot Tiny 2 camera? Is it common for it to heat up and become laggy after about an 60-90 minutes of use? I don’t have AI tracking on and am using this on a Mac.

Slides for #EuroMIP25 are online!

Aye no fair this was a one-one mapping from @sriku.org’s list…

On the follow up list I agree, but given that I don’t know what *I* am up to most of the time, this behaviour is on brand :D

Thanks for sharing this! Turned it into a playable interactive here: interactives.neeldhara.com/knights-puzzle

Damn, me envious!

To be clear, I'm the first to admit I have a problem! Will clean up someday 🙈

Also open always: Granola, Anybox, Mathpix/Screenfloat/Cleanshot, Raycast/Hazel/Alfred/KM/Shortcuts, MacWhisper, Yoink, Dropzone, Popclip

Open-when-needed: Obsidian/Craft/Collections, Screenflow/OBSbot/OBS, VSCode/Cursor/Windsurf (based on wherever I have credits left 👀), Typora, Overleaf, etc.

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So cool! 😎 Are you using the default Apple tools for mail and browsing? My list corresponding to yours would be:

Shortwave/Superhuman, Orion*, Warp*, Obsidian Canvas, RevealJS (via Slides), Zoom, Skim, Bookends, NA, NA, WA/Telegram, Strongbox, Keychain, Fantastical, Godspeed.

*experimental.

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I do get that when you use emacs you don't need anything else, but I think all those modes (?) should count as separate apps for a fair contest.