didericis 6093b8cce3 coloring_nested_tire_graphs: counterexamples to the loose conjecture as stated
Before attempting to prove the loose chain pigeonhole conjecture
("|π(T)| ≥ 6" for every non-trivial cut tire), looked for
counterexamples and found TWO in the existing empirical data:

  (d, face) = (1, 1): 1 out spoke, |π(T)| = 3, orbit size [3].
  (d, face) = (4, 0): 1 out spoke, |π(T)| = 3, orbit size [3].

Reason: a cut tire with exactly k = 1 in/out spoke has σ ∈ {1,2,3}.
S_3 acts with stabilizer of size 2 on any single-color σ, so the
orbit has size 6/2 = 3, never 6. The "|π(T)| ≥ 6" claim is
automatically false for k = 1 tires.

For k ≥ 2: σ can use 1 color (size-3 orbit) or ≥ 2 colors
(size-6 orbit). |π(T)| ≥ 6 requires at least one multi-color σ to
extend, which is not automatic but typically holds.

Three refined conjectures proposed:

  1. Restrict to k ≥ 2 spokes (avoids the trivial counterexample).
  2. Weaken to "non-empty and S_3-closed" (very weak; needs the
     chain composition to preserve non-emptiness).
  3. Just describe orbit sizes 3 or 6 (no useful claim).

The two found counterexamples are at "side" faces in the chain;
they don't break the bottom-line chain pigeonhole because the main
chain runs through larger faces.

To find harder counterexamples: look for k ≥ 2 cut tires whose face
boundary forces all spoke colors equal (= |π(T)| = 3 with k ≥ 2).
Such examples might exist but weren't found in the current data.

Recommended next step: restrict the conjecture to k ≥ 2 and re-run
the empirical sweep.

Note: loose_conjecture_counterexamples.tex (3 pages).

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
2026-05-26 16:24:19 -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
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