didericis e29836c78a coloring_nested_tire_graphs: add general chromatic-polynomial method for §6 graphs
Adds a 'General method' paragraph to menagerie §6 describing how to
compute P_e(G, k) for any G = C_n + (matching of non-crossing chords):

  P_e(G, k) = Σ_{(c_1,...,c_r)} N(C_n; forbidden(c_1,...,c_r), k)

where the sum is over chord-color assignments and N counts proper
k-edge-colorings of C_n subject to per-edge forbidden colors (= the
chord colors at adjacent chord endpoints).  For each chord-color
choice the inner count is a transfer-matrix product on the polygon,
computed in O(n k^2) time, so the full polynomial is computable in
O(n k^{r+2}) time.

The method specializes to the closed form for θ(1, p, q) (r = 1) and
generalizes to any number of non-crossing chords.  Verified against
Sage's chromatic polynomial of the line graph on:
  - θ(1, 3, 3): 30
  - C_8 + {(0,2), (3,7), (4,6)}: 6
  - C_10 + {(0,2), (3,5), (6,8)}: 18

Note grows by ~1/2 page; still 5 pages total.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
2026-05-25 21:53:59 -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%