Hakan Kjellerstrand
hakankj.bsky.social
Hakan Kjellerstrand
@hakankj.bsky.social
Swedish software developer (retired), Independent Researcher mostly in in Constraint Programming and Logic Programming, esp. Picat and Prolog. Also interested in probabilistic programming, inductive programming, math, AI.

Homepage: http://hakank.org/
This is based (and extended) on the findings and data from our first physics paper (preprint): S. V. Chekanov, H. Kjellerstrand: "Discovering the underlying analytic structure within Standard Model constants using artificial intelligence"(arxiv.org/abs/2507.00225 )

5/5
Discovering the underlying analytic structure within Standard Model constants using artificial intelligence
This paper presents a search for underlying analytic structures among the fundamental parameters of the Standard Model (SM) using symbolic regression and genetic programming. We identify the simplest ...
arxiv.org
September 10, 2025 at 7:19 PM
but instead follow a hierarchical structure within a high-dimensional functional space. The found analytic solution depends on only two input parameters, representing the simplest mathematical model that could provide a foundation for developing a future theoretical framework to address the SM.
4/n
September 10, 2025 at 7:19 PM
We outline the core principles of our method and identify the simplest analytic relationships among SM parameters. Our results suggest that the SM parameters associated with quark and boson masses are not randomly distributed,
3/n
September 10, 2025 at 7:19 PM
Abstract: This paper presents an approach to reducing the number of fundamental parameters in the Standard Model (SM) using genetic programming, a machine learning technique based on evolutionary algorithms.
2/n
September 10, 2025 at 7:18 PM
For some examples of how to use the bv module:
* Section "4 Day 17: Chronospatial Computer" of our ICLP'25 paper Picat Through the Lens of Advent of Code (arxiv.org/abs/2507.11731)

* My examples at hakank.org/picat/#bv
GitHub commit of these models: github.com/hakank/hakan...
Picat Through the Lens of Advent of Code
Picat is a logic-based, multi-paradigm programming language that integrates features from logic, functional, constraint, and imperative programming paradigms. This paper presents solutions to several ...
arxiv.org
August 23, 2025 at 8:29 AM
It is a Python program but since it's a beta (about v0.000006), I'll not publish it.

If you're interested, please DM (or mail me).
March 27, 2025 at 5:47 PM
Just for fun, I also asked Google Gemini to do a Deep Research on this problem: docs.google.com/document/d/1...)
and NotebookLM Deep Dive podcast: notebooklm.google.com/notebook/280...

Note that the paper also discusses variants to this puzzle.
Cashier's Change Puzzle Search
Analysis of a Coin Change Puzzle Involving a Cashier 1. Introduction The inquiry concerns a specific logic puzzle presented as a dialogue between a customer and a cashier named Robert. In this scenari...
docs.google.com
March 22, 2025 at 7:16 PM
And I did another Research with Google AI Studio but restricted it to be only on Einstellung Effect. Here's the generated document: docs.google.com/document/d/1...
And then using Google's NotebookLM to create a neat 2 person discussion about the document: notebooklm.google.com/notebook/ef8...
LLMs and Einstellung Effect Research
Large Language Models and the Cognitive Bias of the Einstellung Effect I. Introduction: Defining Large Language Models and the Einstellung Effect in the Context of AI Large language models (LLMs) repr...
docs.google.com
March 15, 2025 at 6:40 PM
Unfortunately. Pop-11 is a fun language and the Poplog distribution contains a huge number of examples of GOFAI (Good Old Fashion AI) that nobody seems to care about nowadays...

Here's my Poplog page:
www.hakank.org/poplog/
My Pop-11 / Poplog page
www.hakank.org
January 30, 2025 at 9:50 PM
Nope, I learned about it some weeks ago so it's on my TODO list. It does seems fun.
One must love a language that has a built-in function for shortest path (www.uiua.org/docs/path). When I browsed the site some weeks ago it had astar but that's now deprecated (in favor of path).
Are you in APL/J/K?
www.uiua.org
January 26, 2025 at 7:56 PM
Thus there are now two "CP" in my life. The real (and for me the first): Constraint Programming, and now Competitive Programming.
I hope that will not confuse neither you nor me.
January 26, 2025 at 7:11 PM
So today I have toggled the autocomplete off. What a mental relief!
January 26, 2025 at 7:07 PM
And now it should work with hakank.org/picat as well
My Picat page
hakank.org
January 24, 2025 at 8:15 AM