dual_decomposition: split iterated reduction into companion paper
- Move the iterated-reduction algorithm, its two structural lemmas
(exactly-one-match, all-distinct-exists), and the n=14 trace figure
into a new companion paper at
papers/dual_decomposition_iterated_reduction/. Figures and figure
scripts moved via git mv (history preserved).
- In the main paper, Section 3 ("An iterated reduction") becomes
Section 3 "Cubic-graph edge contraction" (just the contraction
definition + 4-face theorem).
- Restructure Section 4 to host both the original face-monochromatic-pair
conjecture (clauses 1-3) and its strengthening (adds clause 4) as
separate conjectures, after briefly experimenting with folding them
into one. The empirical evidence is asymmetric (n<=21 for (1)-(3),
n<=18 for the full set), which the two-conjecture split presents more
honestly. The companion-paper reference is now in Section 4's intro.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
This commit is contained in:
@@ -13,30 +13,23 @@
|
||||
\@writefile{lof}{\contentsline {figure}{\numberline {2}{\ignorespaces The proof of Lemma\nonbreakingspace 2.6\hbox {}, illustrated for $i = 0$ on $G' = $ the dodecahedron. Top: under the assumption $W \neq Y$, propriety at $v_n$ forces $W \in \{X, Z\}$. Bottom: in either case the lift to $G'$ has externals satisfying the hypothesis of Lemma\nonbreakingspace 2.4\hbox {}, which colours $\partial F_v$ to extend $\psi $ to a proper $3$-edge-colouring of $G'$.}}{5}{}\protected@file@percent }
|
||||
\newlabel{fig:chord-apex-proof}{{2}{5}}
|
||||
\newlabel{lem:kempe-spike}{{2.7}{6}}
|
||||
\@writefile{toc}{\contentsline {section}{\tocsection {}{3}{An iterated reduction}}{7}{}\protected@file@percent }
|
||||
\newlabel{alg:iterated-reduction}{{3.1}{7}}
|
||||
\newlabel{rem:alg-invariants}{{3.2}{7}}
|
||||
\newlabel{rem:alg-chord-apex}{{3.3}{7}}
|
||||
\@writefile{lof}{\contentsline {figure}{\numberline {3}{\ignorespaces Algorithm\nonbreakingspace 3.1\hbox {} on $G'=\mathrm {dual}(G)$, where $G$ is the first min-degree-$5$ plantri triangulation on $14$ vertices and $\varphi _1$ is a specific proper $3$-edge-colouring of $H_1$ that satisfies both the chord-apex condition (Lemma\nonbreakingspace 2.6\hbox {}) and the Kempe-cycle condition (Lemma\nonbreakingspace 2.7\hbox {}), found by \texttt {experiments/search\_kempe\_property.py}. \emph {Left:} $G'$ ($24$ vertices, $36$ edges) with the chosen pentagonal face shaded. \emph {Centre:} $H_1$ ($20$ vertices, $30$ edges) after step\nonbreakingspace (1) with $i_1 = 1$, $3$-edge-coloured by $\varphi _1$; the four edges around $v_n^{(1)}$ in $E$ are drawn thicker, and the spike and merged edges share the colour green. \emph {Right:} $H_2$ ($16$ vertices, $24$ edges) after step\nonbreakingspace (3) with $i_t = 3$; eight edges are protected, and the algorithm terminates one step later (no remaining safe pentagonal face in $H_2$). The generating script is \texttt {experiments/draw\_iterated\_reduction\_n14.py}; layouts are Tutte barycentric embeddings with the outer face picked to keep $v_n^{(1)}, v_n^{(2)}$ in the interior.}}{8}{}\protected@file@percent }
|
||||
\newlabel{fig:iterated-reduction-trace}{{3}{8}}
|
||||
\newlabel{lem:exactly-one-match}{{3.4}{8}}
|
||||
\newlabel{lem:all-distinct-exists}{{3.5}{9}}
|
||||
\newlabel{conj:face-monochromatic-pair-on-merged-kempe-cycle}{{3.6}{9}}
|
||||
\newlabel{rem:conj-3-6-empirical}{{3.7}{10}}
|
||||
\newlabel{def:cubic-edge-contraction}{{3.8}{10}}
|
||||
\@writefile{lof}{\contentsline {figure}{\numberline {4}{\ignorespaces Cubic-graph edge contraction (Definition\nonbreakingspace 3.8\hbox {}). Left: a fragment of a cubic plane graph with the contracted edge $e = uv$ highlighted in red. Middle: deleting $e$ leaves $u$ and $v$ of degree\nonbreakingspace $2$. Right: smoothing $u$ and $v$ replaces each pair of incident edges by a single new edge, removing $u, v$ and giving a cubic plane graph again.}}{11}{}\protected@file@percent }
|
||||
\newlabel{fig:cubic-edge-contraction}{{4}{11}}
|
||||
\newlabel{thm:cubic-contraction-4face}{{3.9}{11}}
|
||||
\@writefile{lof}{\contentsline {figure}{\numberline {5}{\ignorespaces The recolouring used in the proof of Theorem\nonbreakingspace 3.9\hbox {}. Left: the $4$-face $f$ of $H$ under $\varphi $, with the forced colours $\varphi (e_0) = a$, $\varphi (e_1) = b$, $\varphi (e_2) = \varphi (e_3) = c$, $\varphi (w_0) = \varphi (w_1) = b$, and $\varphi (w_2) = \varphi (w_3) = a$. Right: the contracted graph $H'$ under $\varphi '$. The smoothed-in edges $e_2', e_3'$ inherit the colour $b$ from $w_0, w_1$, and $e_1$ is recoloured from $b$ to $c$; every edge outside the face neighbourhood keeps its $\varphi $-colour (dotted in red: the five edges of $H$ removed by the contraction).}}{12}{}\protected@file@percent }
|
||||
\newlabel{fig:thm-cubic-contraction-4face}{{5}{12}}
|
||||
\@writefile{toc}{\contentsline {section}{\tocsection {}{4}{The Four Colour Theorem from a strengthened conjecture}}{12}{}\protected@file@percent }
|
||||
\newlabel{sec:toward-4ct}{{4}{12}}
|
||||
\newlabel{conj:face-monochromatic-pair-strengthened}{{4.1}{12}}
|
||||
\@writefile{toc}{\contentsline {section}{\tocsection {}{3}{Cubic-graph edge contraction}}{7}{}\protected@file@percent }
|
||||
\newlabel{def:cubic-edge-contraction}{{3.1}{7}}
|
||||
\@writefile{lof}{\contentsline {figure}{\numberline {3}{\ignorespaces Cubic-graph edge contraction (Definition\nonbreakingspace 3.1\hbox {}). Left: a fragment of a cubic plane graph with the contracted edge $e = uv$ highlighted in red. Middle: deleting $e$ leaves $u$ and $v$ of degree\nonbreakingspace $2$. Right: smoothing $u$ and $v$ replaces each pair of incident edges by a single new edge, removing $u, v$ and giving a cubic plane graph again.}}{7}{}\protected@file@percent }
|
||||
\newlabel{fig:cubic-edge-contraction}{{3}{7}}
|
||||
\newlabel{thm:cubic-contraction-4face}{{3.2}{7}}
|
||||
\@writefile{toc}{\contentsline {section}{\tocsection {}{4}{The face-monochromatic-pair conjecture and the Four Colour Theorem}}{8}{}\protected@file@percent }
|
||||
\newlabel{sec:toward-4ct}{{4}{8}}
|
||||
\newlabel{conj:face-monochromatic-pair-on-merged-kempe-cycle}{{4.1}{8}}
|
||||
\@writefile{lof}{\contentsline {figure}{\numberline {4}{\ignorespaces The recolouring used in the proof of Theorem\nonbreakingspace 3.2\hbox {}. Left: the $4$-face $f$ of $H$ under $\varphi $, with the forced colours $\varphi (e_0) = a$, $\varphi (e_1) = b$, $\varphi (e_2) = \varphi (e_3) = c$, $\varphi (w_0) = \varphi (w_1) = b$, and $\varphi (w_2) = \varphi (w_3) = a$. Right: the contracted graph $H'$ under $\varphi '$. The smoothed-in edges $e_2', e_3'$ inherit the colour $b$ from $w_0, w_1$, and $e_1$ is recoloured from $b$ to $c$; every edge outside the face neighbourhood keeps its $\varphi $-colour (dotted in red: the five edges of $H$ removed by the contraction).}}{9}{}\protected@file@percent }
|
||||
\newlabel{fig:thm-cubic-contraction-4face}{{4}{9}}
|
||||
\newlabel{rem:conj-3-6-empirical}{{4.2}{9}}
|
||||
\newlabel{conj:face-monochromatic-pair-strengthened}{{4.3}{10}}
|
||||
\newlabel{rem:conj-3-8-empirical}{{4.4}{10}}
|
||||
\newlabel{rem:implication-4ct}{{4.5}{10}}
|
||||
\newlabel{tocindent-1}{0pt}
|
||||
\newlabel{tocindent0}{0pt}
|
||||
\newlabel{tocindent1}{17.77782pt}
|
||||
\newlabel{tocindent2}{0pt}
|
||||
\newlabel{tocindent3}{0pt}
|
||||
\newlabel{rem:conj-3-8-empirical}{{4.2}{13}}
|
||||
\newlabel{rem:implication-4ct}{{4.3}{13}}
|
||||
\gdef \@abspage@last{14}
|
||||
\gdef \@abspage@last{11}
|
||||
|
||||
Reference in New Issue
Block a user