Skip to content

Instantly share code, notes, and snippets.

View Nikolaj-K's full-sized avatar
💭
I'm combinating Why's.

Nikolaj Kuntner Nikolaj-K

💭
I'm combinating Why's.
  • DLR Germany, IST Austria, Infineon, ...
  • Vienna
View GitHub Profile
@Nikolaj-K
Nikolaj-K / CZF_vs_von_Neumann.md
Last active March 20, 2026 16:06
Truth values, modified Powerset operation and Neumann stages in constructive ZF

Script for the video discussed at

https://youtu.be/yRXxBsy2Z6c

CZF's characterization of the von Neumann "hierarchy"

In this video we analyze how much we get without LEM or the Powerset axiom. (But with function spaces and the very set theoretical Replacement.) That context has semnatics where all sets are in the surjective image of a subset of ${\mathbb N}$. (Subcountability, see also subquotients.)

@Nikolaj-K
Nikolaj-K / coding_rank_cardinality.md
Created March 12, 2026 17:45
Impact of coding on rank and cardinality

This is the script for the video discussed at

https://youtu.be/7gbRTShKvp8

Cardinality individual coded reals

Z_2 reals

Constrain $d_i > 0, s_i\in{0,1}$.

$i\mapsto \tfrac{n_i}{d_i}(-1)^{s_i}$ in ${\mathbb Q}^{\mathbb N}$

@Nikolaj-K
Nikolaj-K / local_wallet_codex_prompt.md
Last active February 21, 2026 13:15
Local wallet Codex prompt

Dowload the Codex UI at

https://chatgpt.com/codex/

  • log in with your OpenAI (I assume you're on a mac here)
  • create a new empty folder somewhere and then with Codex open a project/thread in there
  • set it to Gpt-5.3-Codex (maybe Extra High)
  • (during runtime you might progressively want to say Yes to various permissions - you won't go far apart from downloading python stuff if you don't have it)
  • start chatting with it a bit, then dump in the following longer prompt at once:
@Nikolaj-K
Nikolaj-K / churchs_thesis.md
Last active February 1, 2026 11:05
Gödelian arithmetization and the anti-classical Church's thesis

This is the script discussed in the video at

https://youtu.be/gNSv2kWRv88

Gödel arithmetization and the anti-classical Church's thesis

Outlook for this video:

  • On the arithmetization of proof
  • On Gödel incompleteness with emphasis on quantifiers
  • Note on Existence and Disjunction property
  • Note on the failure of the Least Number Principle
This script is explained at
https://youtu.be/53lvGfk9ib8
For all $n$,
$\int_{-\pi}^\pi\, x^{2n} \left(\dfrac{2}{1 + {\mathrm e}^{\sin(x)}}\right){\mathrm d}x = \int_{-\pi}^\pi x^{2n} \,{\mathrm d}x$
$\dfrac{2}{1+{\mathrm e}^x} = 1 - \tanh(\frac{1}{2}x)$
@Nikolaj-K
Nikolaj-K / logsumexp_vs_max.md
Created January 9, 2026 17:46
Quickie on LogSumExp vs Max

Video where this script is discussed: https://youtu.be/Lsf4eAGvODs

Consider a non-strictly ordered space $X$ with an (absolutely homogenous) absolute value function $|\cdot|: X\to X$ If $B:(X\times X)\to X$ is a symmetric map, then

$B(\max(x, y)-x, \max(x, y)-y) = B(0, |x-y|)$

Proof

@Nikolaj-K
Nikolaj-K / wiki_page_searcher.py
Last active December 31, 2025 19:19
Minimal Wikipedia semantic search wrapper for web integration.
#!/usr/bin/env python3
"""
Minimal Wikipedia semantic search wrapper for web integration.
Install hints (CPU):
- python, duh
- pip install -U sentence-transformers faiss-cpu numpy
Expected index artifacts (see zip):
- path/to/pages_embeddings.index (main data item, 200 MB)
@Nikolaj-K
Nikolaj-K / applied_optimization_2025.md
Last active December 17, 2025 10:19
Applied Optimization 2025, exercises and some eotes

This file starts with Exercises, which ends at exercise 10 and is followed by "Notes: Applied Optimization".

Search for "Exercise 9" for the Regression cost function minimization exercises.

Greetings Nikolaj Kuntner


Exercises - Applied Optimization

@Nikolaj-K
Nikolaj-K / glasser.md
Last active November 21, 2025 18:34
Visualizer for Glasser transform type theorems

Script for the video

https://youtu.be/LfiIiSPg3Ms

$f$ ... Lebesgue-integrable over (all of) ${\mathbb R}$,

$\int_{-\infty}^\infty f\big(x + d\big),{\mathrm d}x = \int_{-\infty}^\infty f\big(x\big),{\mathrm d}x$

$\int_{-\infty}^\infty f\big(x - \dfrac{1}{x}\big),{\mathrm d}x = \int_{-\infty}^\infty f\big(x\big),{\mathrm d}x$

@Nikolaj-K
Nikolaj-K / prob_theory_midterm.md
Last active November 13, 2025 13:15
Probability Theory Statistics Master Midterm

Probability Theory 1 – Script skeleton

  • 2024W-Prob1__script.pdf: sections 1–5 (up to and including 5. Lebesgue-Integral)
  • 2025W-Prob1-Collection.pdf: sections 0–3 (up to and including 3. Das Lebesgue-Integral)

Notes:

  • Warning: I dropped \mathcal, since it doesn't render in gist
  • Likewise, _\# became _H
  • The items have rough importance rankings
  • roughly "important" vs "neutral" and "random"; I'll derank a few later