didericis 53a676971c coloring_nested_tire_graphs: define "cut tire" with multi-depth visualisation
Adds Definition (cut tire) to cut_depth_label.tex:

  Given the depth labelling on G'_i, for each d > 0 let H_d be the
  subgraph on depth-d edges (with inherited planar embedding).  For
  each face f of H_d, the cut tire at (d, f) is the subgraph of G'_i
  consisting of:
    - every edge on the boundary walk of f (all depth d), and
    - every edge of G'_i incident to the boundary walk of f with
      depth d-1 or d+1.

The depth-d edges form the "face boundary"; the d-1 edges are
"inner spokes" (toward the cut); the d+1 edges are "outer spokes."

This is the dual-side analogue of the tire annular face connector
T'_{f'} (paper.tex Def. 1.16):
  face boundary ↔ T'_ann (annular subgraph at depth d)
  cut tire     ↔ T'_{f'} (annular face connector)
  inner/outer spokes ↔ inner/outer spokes of T'_{f'}

Adds experiments/cut_tire.py producing fig_cut_tire.png:
5-panel visualisation of cut tires at depths d = 1, 2, 4, 5, 6 on
G'_1 (V\S half of Holton-McKay #0). Outermost tire at d=1 (face
length 12, 5+4 spokes); innermost at d=6 (face length 12, 7+1).

Note grows from 3 → 5 pages.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
2026-05-26 15:32:47 -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

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./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]
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  • 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

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./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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