didericis 84600dadd3 coloring_nested_tire_graphs: joint-projection chain DP + tree-H_d coverage gap
NEW: chain_dp_joint.py — chain DP tracking full per-tire colorings,
edge-tuple-based parent/child sharing, and ground-truth comparison
against brute-force G' edge-coloring enumeration.

KEY EMPIRICAL FINDING (4th issue in chain_half_analysis):
When H_d is a tree (no internal cycles), the high-side cut tire
forest is EMPTY.  The single H_d face is forced (by the level-set
lemma) to be entirely low-side or high-side; for a tree containing
the pendants, it's low-side.  Hence high-side forest has 0 tires.

This happens at dodecahedron cut #0 side 0 (|S_0|=4):
  - depths {0: 2, 1: 3}, |H|=6, |E(H)|=5
  - H_1 is a tree, 1 face of length 6 (= low-side)
  - No high-side cut tires
  - DP gives R_dp=0, but ground truth R=36

DP correctly produces non-empty output on side 1 (where H_1 has
2 faces, one high-side), but the high-side framework's coverage
is incomplete for thin (small |S_i|) cuts.

This is a STRUCTURAL gap, not a code bug.  The path forward
suggested in chain_half_analysis.tex: introduce a "boundary cut
tire" T_0 representing the low-side face + its pendants, so the
chain DP runs from leaves through T_0 to the cut.

Compounding with prior gaps:
  (1) cut tires aren't always spoke-only (branched H_d faces)
  (2) OUT-only projection loses S_3 orbit
  (3) heuristic parent-finding (vertex overlap)
  (4) tree H_d → empty high-side forest (this commit)

Net: the loose conjecture's chain half is genuinely open and
requires framework extension before the DP can be tested cleanly.
S_3 equivariance and high-side forest structure are the proven
pieces.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
2026-05-26 22:58:21 -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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