didericis 246b8914e7 face_monochromatic_pairs: refine S-cycle analysis; G'-pentagon fallback needs strengthening
experiments/check_S_face_structure.py: detailed analysis of S-cycle
structure for the 1,314 bad chord-apex+Kempe colourings.

Findings:

1. S-cycle is NEVER a face boundary of the reduced dual (0% across
   all |S| from 2 to 10). So the S-cycle's "interior" contains
   additional faces.

2. Refined pigeonhole + p_G ≥ 7 + S-cycle structure closes:
   - |S| = 2: max hit 2 < p_G ≥ 7. ✓ 420 / 1314.
   - |S| = 4: max hit 4 < p_G ≥ 8. ✓ 258 / 1314.
   - |S| = 6: max hit 7 < p_G ≥ 8. ✓ 348 / 1314.
   - |S| = 10: max hit 7 < p_G ≥ 8. ✓ 36 / 1314.
   Total: 1062 / 1314 = 80.8% of bad colourings closed.

3. |S| = 8: max hit = 8 = min p_G (sometimes). ≤ 30 colourings
   (~2.3% of bad, ~0.02% of full 142,812) have ALL G'-pentagons hit
   by S — so the G'-pentagon fallback (Conjecture 5.X) is
   EMPIRICALLY FALSE in this sub-case! For these, the deciding face
   must be a G'-heptagon (length 7) or G'-octagon (length 8), not a
   pentagon. Both lengths are ≢ 0 mod 3 and so still serve as
   deciding faces.

So the structurally-correct fallback is "G'-face of length ≢ 0 mod 3",
not "G'-pentagon" specifically. This is consistent with the
deciding-face data: 462 incidences of length-7 G-prime-faces, 6 of
length-8.

Combined structural coverage:
  - Tight cases (a', b', c): 91% (1,205 / 1,314 plus full-coverage cases)
  - Refined pigeonhole: 80.8% of bad colourings = 1062 / 1314
  - Total: ≈ 99.5% of full 142,812 chord-apex+Kempe colourings
    structurally proven.

The remaining ~0.02% (30 colourings) need a structural argument that
some G'-face of length ≢ 0 mod 3 always exists with boundary in
V(K_b) ∪ V(K_c).

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
2026-05-25 06:57:20 -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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