didericis 7cd1f0d08d coloring_nested_tire_graphs: chain pigeonhole on pendant-redefined cut tires
New note cut_tire_chain_pigeonhole.tex (4 pages) examining what
chain pigeonhole looks like under the redefined cut tire (face
boundary + labelled pendants).

KEY CHANGE: each cut tire is now structurally isomorphic to a partial
tire dual D(T), so all results from paper.tex / rainbow_proof.tex /
worst_case_proof_sketch.tex / k9_surviving_partitions.tex transfer
directly without re-derivation.

ARGUMENT SHAPE:
  Setup: min counterexample G', 6-edge cut, depth labelling, cut
  tires at each depth.

  Reduction: minimality ⇒ G'_i 3-edge-colorable ⇒ boundary
  configurations σ_0, σ_1.

  Layered: σ_i = π_out({T_1^{(i, f)}}). Chain compatibility:
  out spoke of T_d ↔ face boundary edge of T_{d-1} via the
  parent-graph correspondence.

  Pigeonhole: if at each layer the projection support contains
  S_3-symmetric structure, the chain propagates and forces
  R_0 ∩ R_1 ≠ ∅.

WHAT'S NEW UNDER THE REDEFINITION:
  1. Direct result transfer: cut tires LITERALLY are partial tire
     duals; no translation overhead.
  2. Cubicity restored: face-boundary vertices have degree 3 in the
     cut tire (degree 2 in H_d + 1 pendant).
  3. Combinatorial rigidity: cut tire data = face + degree-2 boundary
     vertices + in/out classification.

WHAT STAYS OPEN:
  (a) Chain pigeonhole at each layer: same conjectures (rainbow,
      König-lift) gate the argument.
  (b) Chain well-definedness: trivial H_d faces (length 2),
      degree-> 2 boundary vertices not getting pendants.
  (c) Depth-by-depth variability: no uniform bound on |π_out|
      across depths.

ASSESSMENT: strict improvement over the previous cut tire definition
(no transfer overhead, cubicity restored), but the hard step
remains the same as in the partial-tire-dual framework.

Concrete next step: cut-tire analogue of tire_fiber_step2 — for
each Holton-McKay graph, build cut tire chains on both sides of a
6-cut and check R_0 ∩ R_1 empirically.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
2026-05-26 16:00:15 -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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