didericis 8b6c2b621c split: extract foundational depth material into new plane_depth paper
Splits the existing plane_depth_sequencing paper into two:

  papers/plane_depth/paper.tex (NEW, 4 pages):
    - Plane depth definition.
    - Level edge, up/down/neutral triangle classification.
    - Outerplanarity lemma (formerly Lemma 2.6 of PDS).
    - Deep embedding G' definition.
    - "Every face of G' is up or down" lemma.
    - Unique level edge per face; shared level edge between adjacent faces.
    - Quadrilateral decomposition definition with three types
      (shallow diamond, deep diamond, S quad).

  papers/plane_depth_sequencing/paper.tex (slimmed from 11 → 6 pages):
    - Cites plane_depth for all foundational definitions.
    - Keeps: slice, move definitions (anchor drop, level add, join,
      ring completion), move selection, termination theorem.

  papers/coloring_nested_tire_graphs/paper.tex:
    - Bibliography updated: cite bauerfeld-depth instead of bauerfeld-pds.
    - Two in-text references updated to cite the new outerplanarity
      lemma in plane_depth.

Rationale: the outerplanarity / deep-embedding / quadrilateral-
decomposition material is foundational and reused by multiple
papers (and by the proposed level-cycle generalization).  The
quadrilateral-sequencing programme is one specific application.
Splitting lets coloring_nested_tire_graphs cite the foundations
cleanly without dragging in the sequencing machinery.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
2026-05-26 13:49:44 -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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