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Ask HN: What did you learn last month? (July 2026)
11–20 of 21 posts
Re: Ask HN: What did you learn last month? (July 2026)
#12Quantum Mechanics (ongoing), Sturm-Lioville theory, Special Relativity (ongoing), Tensors (going towards General Relativity) What finally clicked: Hermitian matrix, self-adjoint operators, quantum operators for energy and momentum, the Metric (for modeling spacetime curvature), etc.
What's the story of the Hermitian matrix and self adjoint operators?
Would be hard to explain without some equations. Here's an outline:
Nature follows differential equations.
Differential equations are generally complex to solve but have properties that are helpful. E.g., a second order differential equations would have two independent constants of integration in the solution. If two have already been found, a third independent one won't be needed and you already know that you have a complete solution.
For linear equations, if you find enough orthogonal basis functions that are each a solution, even if by hook or crook, you would have found all solutions.
Some functions and operators yield a function with the same form as the original function. E.g., derivative of exponentiation, second derivative of sine, etc.
The differential equation can happen to be such that a function of the above type then cancels out from the equation. This simplifies the equation.
If the above process yields enough orthonormal basis functions, then we know we have the entire space of solutions.
When the operator happens have some properties, the above happens.
Euler's equation links exponential to sine and cosine. That makes complex numbers useful. Then exponentiation covers sine and cosine too.
Magnitude of complex numbers is the number multiplied by its complex conjugate.
The math proofs extend from real numbers (actually needed by Physics) to complex numbers by using complex conjugates.
Hermitian matrices and self-adjoint operators are special cases that bring orthogonal basis functions, real-valued solutions (in spite of using complex numbers), etc.
References:
Spectral Theorem
Sturm Liouville Theory
Re: Ask HN: What did you learn last month? (July 2026)
#13I had not "vibe-coded" at all. I decided to learn I would build a game I would be passionate about. I jumped in head first with Claude Code and am absolutely blown away with the power and ease of use. I went from just an idea to a v1 prototype to a staging environment for 2.0 to production 2.0 with even more features than I initially planned in less than a month. The lesson is, if you're brand new, like I was, just jump in and use the tools for something you care about. You will quickly learn more than you thought possible and have fun at the same time.
Re: Ask HN: What did you learn last month? (July 2026)
#14I had not "vibe-coded" at all. I decided to learn I would build a game I would be passionate about. I jumped in head first with Claude Code and am absolutely blown away with the power and ease of use. I went from just an idea to a v1 prototype to a staging environment for 2.0 to production 2.0 with even more features than I initially planned in less than a month. The lesson is, if you're brand new, like I was, just j…
Did you write code before? Or was it heads first straight with Claude Code? Do you recommend non-coders this approach to build something of their own?
Re: Ask HN: What did you learn last month? (July 2026)
#15I had not "vibe-coded" at all. I decided to learn I would build a game I would be passionate about. I jumped in head first with Claude Code and am absolutely blown away with the power and ease of use. I went from just an idea to a v1 prototype to a staging environment for 2.0 to production 2.0 with even more features than I initially planned in less than a month. The lesson is, if you're brand new, like I was, just j…
Did you write code before? Or was it heads first straight with Claude Code? Do you recommend non-coders this approach to build something of their own?
No, I don't write code at all. I'm in engineering leadership and manage many engineers (devs, SREs, QAs, etc.) but am not a software engineer myself. The goal for me was to really understand the landscape and to be able to confidently speak about the tools from first-hand experience, not just what I read daily. I absolutely recommend non-coders check the coding tools out. If you were trying to become a coder it may not be the best approach to start that way, but if you're someone who has ideas that you want to build and iterate on without needing to involve a coder, and learn a ton about all the design aspects, hosting considerations, etc. it's gold (bit much cheaper).
Re: Ask HN: What did you learn last month? (July 2026)
#16I spent some time learning about healthspan, how to stay healthy as you age. It is something which I have had an interest in for a long time. I am focusing on staying ten years ahead with my health.
Re: Ask HN: What did you learn last month? (July 2026)
#17Learned the basics of IBM Z mainframe stuff, and got a "credly" thing on my LinkedIn. IBM actually said congrats.
Just started their COBOL course now.
Re: Ask HN: What did you learn last month? (July 2026)
#18That finishing a website and getting Google to index it are two completely different projects. I shipped a few hundred pages, all technically clean (now), and most of them have been sitting in "Discovered, currently not indexed" status MY AI coding assistant tells me a new domain with no external links just doesn't get crawl priority, and no amount of extra on-site work will change that.
Two specific mistakes I did fix along the way: my landing page force redirected visitors to their browser language, which can hide the other language versions from crawlers. Google's own docs say offer, don't force. And my internal links pointed at page.html while my sitemap said /page, so Google was discovering every page at one address and being told the real one was another. This could have also contributed to the limbo my website is in (although Gemini says that that doesn't happen). Fingers crossed
Re: Ask HN: What did you learn last month? (July 2026)
#19[dead]
Re: Ask HN: What did you learn last month? (July 2026)
#20I started learning how cars work through a website called howcarswork.com It seems though the project was canceled halfway through. does anyone know if he ever plans on finishing it?