didericis adafecc75b coloring_nested_tire_graphs: redraw Figure 4 with barbell O (real chord)
Replaces the spoke-only Figure 4 with a true barbell example:

Setup:
  - B_out: hexagon u_0..u_5 (red).
  - O = barbell: triangle {a_1, a_2, a_3} + triangle {b_1, b_2, b_3}
    + bridge a_3-b_1 (light red).
  - 14 spokes triangulate the annulus into 14 annular triangles:
    6 outer-cap + 6 inner-cap + 2 bridge-cap.

Dual placement is precise:
  - All 14 blue dots at exact triangle centroids (via TikZ
    barycentric cs).
  - 13 edges of the Hamilton cycle wrap around the annulus
    crossing each spoke.
  - The bridge dual edge connects the two bridge-cap triangles
    directly (dashed blue chord across the cycle).

Resulting Γ ≅ Θ(1, 7, 7): Hamilton cycle of length 14 with a
single length-1 chord. Outerplanar (the length-1 chord has no
internal degree-2 vertex, so no K_{2,3} minor).

This now properly demonstrates the chord arising from a real
bridge, exactly as the theorem and Remark 1.14 describe.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
2026-05-27 02:24:46 -04:00
2026-04-12 22:23:55 -04:00
2026-04-20 16:32:27 -04:00
2026-04-20 16:32:27 -04:00
2026-04-20 17:00:04 -04:00
2026-04-20 16:32:27 -04:00
2026-04-17 00:54:42 -04:00
2026-05-09 11:34:58 -04:00

math-research

Personal mathematics research repository by Eric Bauerfeld. Papers are written in AMS-LaTeX using the amsart document class.

Papers

kempe_style_search_for_smaller_contradiction

Humans Suffice: A Novel Proof of the Four Color Theorem

An in-progress proof of the Four Color Theorem via a minimal counterexample argument. The paper builds on Kempe's 1879 strategy — establishing valid cases for vertices of degree ≤ 4, then extending the argument to the degree-5 case using properties of non-adjacent degree-5 vertices, merged subgraphs, and locked colorings.

plane_depth_labelling

Plane Depth Labelling

Early-stage paper. Title and author information set; content in progress.

Creating a New Paper

Use run.sh to scaffold a new paper from the AMS-LaTeX template:

./run.sh init_paper "Your Paper Title"

This creates a new directory (name derived from the title) containing a paper.tex pre-filled with the title and author.

Setup

The Python library code in lib/ requires SageMath. Run setup once per machine:

./run.sh setup <sage_python_path> <sage_site_packages> [system_name]
  • sage_python_path — path to the SageMath Python interpreter (e.g. /opt/sage/local/bin/python3)
  • sage_site_packages — path to SageMath's site-packages directory
  • system_name — optional label for this machine (defaults to hostname -s); used to store per-machine env files as .env.<system_name>

On subsequent runs the paths default to whatever was saved in .env, so ./run.sh setup alone re-runs setup with the existing configuration.

Setup also compiles the plantri submodule via make.

Running Sage

To run a Sage script with plantri available on PATH:

./run.sh sage <script.py> [args...]

Or to open an interactive Sage session:

./run.sh sage

Linting

./run.sh lint

Runs pyright and pylint on lib/ using the SageMath Python interpreter.

Shell Completion

To enable tab-completion for run.sh in zsh, add this to your .zshrc:

eval "$(path/to/run.sh completion)"

Or source it once in the current shell session:

eval "$(./run.sh completion)"

Building

Papers are compiled with LaTeX. From within a paper directory:

latexmk -pdf paper.tex
S
Description
No description provided
Readme 277 MiB
Languages
Python 69%
TeX 30.8%
Shell 0.2%