“Holey Cow” - a children’s book. Written by me. Illustrated by my mom (@AnaDwork). a.co/d/czL7N7f

"Duality in Optimization: A Visual Tutorial" (by Mohini Bariya): arxiv.org/abs/2609.23751

"Introduction to Quantum Mechanics" is a free textbook that clearly introduces the mathematical foundations of quantum mechanics. Despite the subject's complexity, it is quite accessible if you already have a strong background in calculus, linear algebra, and differential equations. The book covers the origins of quantum mechanics and develops the Schrödinger equation, Hilbert spaces, operators and eigenvalues, Dirac notation, the uncertainty principle, and symmetry and conservation laws. It then moves on to solutions of the Schrödinger equation, finite and infinite square wells, tunneling, the harmonic potential, the hydrogen atom, angular momentum, spin, entanglement and Bell's inequality, perturbation theory, and the electronic structure of atoms, molecules, and solids. I think it's an interesting read if you want to explore the mathematics behind quantum mechanics, one of the most fascinating areas of modern physics. gitlab.tudelft.nl/opentextbo…

Matthew Colbrook, George Stepaniants, Françoise Tisseur, and Alex Townsend have launched NLA-explained, a public library of readable explanations of proofs in the Open Problems in Numerical Linear Algebra collection. nla-explained.com/

I reread this every year. I cry like a baby every year. Todd Beamer died a father, husband, and hero. Todd: Hello… Operator… listen to me. I can’t speak very loud. This is an emergency. I’m a passenger on a United flight to San Francisco. Our plane has been hijacked. Lisa: I understand. Can they see you? Todd: No. There are three that we know of. They have knives — razor knives, like box cutters. Someone announced from the cockpit there was a bomb. It sounded fake. Lisa: Your name?Todd: Todd Beamer. United Flight 93.Todd: They killed one passenger in first class. They forced most of us back. Fourteen of us here. Five flight attendants. The guy with the bomb ordered us to sit on the floor. Lisa: Are you okay? Todd: We’re going down… wait. No. We’re leveling off. We changed directions. We’re flying east again. Todd: A guy named Jeremy called his wife. She told him two planes hit the World Trade Center. Lisa, is that true? Lisa: I have to tell you the truth. It’s very bad. Both towers are gone. A third plane hit the Pentagon. Our country is under attack. I’m afraid your plane may be part of their plan. Todd: Oh God. Lisa, will you do something for me? Call my wife and my kids. Promise me you’ll call. Lisa: I promise. Todd: Our home number is… You have the same name as my wife. Lisa. We’ve been married ten years. She’s pregnant with our third child. Tell her I love her. I’ll always love her. We have two boys — David, he’s 3, and Andrew, he’s 1. Tell them their daddy loves them and he is so proud of them. The baby is due January 12th. I saw an ultrasound. We still don’t know if it’s a girl or a boy. Lisa: I’ll tell them. I promise, Todd.(Lisa patches in the FBI.) Agent: Todd, your plane is on a course for Washington. Best guess is the White House or the Capitol. Todd: I understand. I’ll be back. Todd: Everyone knows this isn’t a normal hijacking. We have decided we will not be pawns in their plot. Lisa: What are you going to do? Todd: Four of us are going to rush the one with the bomb. Then the cockpit. A stewardess is getting boiling water. We’ll take them out. Todd: Would you pray with me?They pray the Lord’s Prayer. Then: Yea, though I walk through the valley of the shadow of death, I will fear no evil, for thou art with me. Todd: God help me. Jesus help me.Are you guys ready? Let’s Roll.

In an excellent math book I was reading:

A 7% raise is actually a pay cut. shadowstats.com/alternate_da…

Computer scientist Sara Hooker on underestimating difficulty:

Harnesses often get dismissed as just scaffolding, just prompt engineering, and not real research. But that couldn't be farther from the truth. The same model weights that score 30% on ARC-AGI score 95% with a better harness. So we gathered a group of researchers and founders working at the frontier to do a deep dive into the state of harnesses. We cover how we got to this point, the case for making your harness as expressive as possible, and what YC learned building an agent for every employee in the company. 00:00 - @FrancoisChauba1: Why harnesses matter 04:27 - Building an auto-researcher by accident 07:13 - A five minute history of harnesses 13:56 - Self-improving harnesses 18:35 - @sethkarten: Prime Agent, a self-improving RLM harness 21:50 - Context as an L1, L2, L3 cache 24:51 - From Turing machine to von Neumann computer 28:33 - Messaging between agents 30:04 - ARC-AGI results 33:09 - Emulator Bench and GPU kernels 37:30 - @JonSaadFalcon: OpenJarvis, personal AI on personal devices 38:26 - How far behind are local models 39:21 - The five primitives of a personal AI stack 42:47 - Letting cloud models optimize your local stack 43:53 - 800x cheaper than the cloud 45:58 - @josh__france and @jbellregan: QM, YC's agent harness for work 47:29 - A history of YC's internal agents 49:24 - OpenClaw and a fleet of 50 agents 51:04 - Pulling the brain out of the sandbox 54:43 - Letting the agent choose its own sandbox and model 57:16 - The grind tool: budgets on goals 58:50 - Agents don't understand social context

After years of working in electronics, this feels like a full circle moment. Many late nights later we are releasing Atlas Fields Studios, free for everyone fields-studio.arenaphysica.c… The Fields Studio App lets you explore electromagnetic behavior around PCB designs #buildinpublic

"Mathematics of Data Science" is a recent, freely available textbook, published in July 2026, specifically written for anyone interested in understanding the mathematics behind the fundamental concepts, methods, and applications of modern data science. The book covers high-dimensional geometry and probability, concentration of measure, singular value decomposition, principal component analysis, linear regression and regularization, nonlinear dimensionality reduction, diffusion maps, random projections, optimization, classification, support vector machines, generalization bounds, and much more. Chapter 5 is particularly interesting. It is entirely dedicated to graphs, networks, and clustering, including k-means and spectral clustering. It also provides an intuitive mathematical explanation of Google PageRank, showing how the structure of links between web pages can be represented and analyzed to estimate their relative importance. The sections on classification problems are also worth reading. They cover binary and linear classifiers, logistic regression, confusion matrices, ROC analysis, support vector machines, multiclass classification, and the mathematical foundations of generalization. arxiv.org/pdf/2607.11938

Oh no. Tell the truth, or at least don’t lie. -@jordanbpeterson

It feels like someone throwing sand onto train tracks in order to try and stop a runaway train. While the treasury is trying to fight higher interest rates, the government is increasing its debt at record rates, now at $40T and that's without unfunded liabilities!

On July 2, 1982, a 33-year-old truck driver named Larry Walters tied 42 helium weather balloons to a Sears lawn chair, strapped on a parachute, packed a BB gun, sandwiches, and a six-pack… and cut the rope. He expected to float a few hundred feet over his San Pedro backyard. Instead he shot up like a rocket to 16,000 feet — straight into the main approach path for LAX. Two airline pilots radioed the tower: they had just passed a man in a lawn chair holding a gun at 16,000 feet. For 45 minutes he floated over Los Angeles, freezing, too scared to shoot more balloons. Finally he started popping them one by one and came down tangled in power lines in Long Beach, blacking out part of the neighborhood. When police asked why he did it, he said: “A man can’t just sit around.” FAA fined him $4,000. America turned him into a folk hero — Lawnchair Larry. True story.

Extended version of my talk from ENGAGE about teaching conformal geometry (useful for animation, cosmology, electromagnetism, quantum mechanics etc) using Geometric Algebra 🙂 edited from my recent stream piped.video/GKzZi9BMt0c

Jeff Hinton dismissed gradient descent in the 1970s because he thought models would get stuck. He won the Nobel Prize in 2024 partly for being wrong about that. Every time ChatGPT gets better after a training run, it's because 1.2 billion parameters fell through a wormhole in a loss landscape - not because they crawled downhill one step at a time. This video visualizes exactly what that looks like inside Llama 3.2. 20 minutes. Bookmark & watch today. The misconception that almost stopped AI is more interesting than the solution.