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math-research/papers
didericis f0bc82b88d coloring_nested_tire_graphs: compare 2-SAT vs König-lift approaches to chain pigeonhole
Adds a side-by-side comparison of the two proof attempts now in
the repo:

  Approach 1 (cyclic 2-SAT, in rainbow_proof.tex):
    Proves π_D = P_m (perms-per-half) for one antipodal-chord SP
    tire when m_1 ≥ m - 1.  Open piece: 2-SAT solvability
    (Conjecture 1.5).

  Approach 2 (König lift, in worst_case_proof_sketch.tex):
    Proves |S_1 ∩ S_2| ≥ 6 for two adjacent SP tires sharing γ
    when both chords are on γ.  Open piece: T_2 induces a
    γ-face partition (Conj t2-induces-partition).

Assessment: Approach 2 is more promising because (a) the hard step
is already proven (König's theorem), (b) it proves exactly what we
need (chain-pigeonhole non-emptiness, not the full π_D
characterisation), and (c) it directly explains the empirical
worst-case |S_1 ∩ S_2| = 6 = single S_3-orbit phenomenon.

Approach 1 still has value if we need finer control over π_D's
shape, but for just establishing non-empty overlap Approach 2
suffices.

Both approaches witness the SAME canonical 6-element worst-case
intersection (the rainbow S_3-orbit at γ=6 = the König-lifted
Latin S_3-orbit).

Recommended next move: attack Conj t2-induces-partition.  Write
down the candidate induced γ-partition explicitly, verify it
computationally, then prove inclusion via transfer-matrix / fibre
lifting.

Note: two_approaches_comparison.tex (3 pages).

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
2026-05-26 11:19:39 -04:00
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