Publications / zero-rotatability-47-edge-arm-spiders

Zero-rotatability for spiders with 47-edge arms

For every n ≥ 2 and m ≥ 0, each actual vertex of S(47^n,1^m) can be the unique zero in a graceful labeling; a separate labeling may be used for each target.

Let S(47^n,1^m) be the spider with n named arms of 47 edges each and m original unit leaves at the center. For every n ≥ 2, m ≥ 0, and every actual vertex v, there is a graceful labeling f with f(v)=0 and f(w)=0 exactly when w=v. This covers the center, every depth 1 through 47 on every named arm, and each original leaf when present. The labeling may depend on v. The result concerns the fixed arm length 47; it is not a theorem for all odd arm lengths.

The proof combines 95-vertex graceful path labelings with a prescribed midpoint and a zero or maximum at a specified distance, the classical alpha-amalgamation operation described by Shan and Zhong with a residual spider labeling, and separate constructions for the center, original leaves, and arm tips. A Lean 4.34.0 formalization and a separate copied-source replay check the theorem; these are internal project checks.

Earlier work covers the complete path case S(47^2,1^0)=P95 and the case with one center leaf, S(47^2,1^1), including every vertex. Bahls, Lake, and Wertheim give ordinary graceful labelings for equal-arm spiders with no center leaves, using a hub-zero construction for odd numbers of arms. These results are relevant overlaps but do not by themselves state the full all-n,m all-vertex theorem here. Historical priority remains unknown.

Statements & evidence

K47-ALL-ACTUAL-VERTEX-UNIQUE-ZERO-ROTATABILITY Proof provided

For every n ≥ 2, m ≥ 0, and every actual vertex v of S(47^n,1^m), there exists a graceful labeling f with f(v)=0 and, for every vertex w, f(w)=0 if and only if w=v.

Formal verification
Formally verified within the stated scope
Review status
Internal check
Evidence
Independent mathematical composition report SHA-256 13a6cb3187b1f9b60105c58479f46f32b477f686f5353ae63657321342c51ee9; Lean author freeze report SHA-256 307c01ce4ec332f14d8df7cb83e044909f19d5d41c7d46994bdf2d4ff93ad0fb; independent copied-source Lean replay report SHA-256 1b23169d1826803a4e3e38a2a4897ba62d48f82715757d7890e095362ff2f4de; bounded primary-literature assessment report SHA-256 887ef1e18439e8e93ae090ac3a38586c511bde3961dbe82e7361f5aac07b1a2f.
Scope
For all n≥2,m≥0, every actual named vertex of S(47^n,1^m), including center, every depth 1..47 on each named arm and all original center leaves when present; the selected vertex is the unique zero in a possibly target-specific graceful labeling. The graph has 47n+m edges and the standard graceful label and weight ranges.
Assumptions
S(47^n,1^m) is the finite spider with n named arms of exactly 47 edges and m original unit leaves attached to the center. Graceful means a bijection of vertices to 0..|E| whose absolute edge differences biject to 1..|E|. The labeling can depend on the selected target vertex and has no other zero.
Toolchain
Lean 4.34.0; 42 modules freshly compiled with -DwarningAsError=true in author freeze and separate copied-source replay; principal theorem GracefulBoundary.K47Full.all_vertices_unique_zero; internal mathematical composition check. Standard Lean kernel verification.
Reviewer
Internal mathematical composition audit and separate copied-source Lean replay only; no external or peer review is claimed.

Files & reproduction

No files attached.

Contributions & AI assistance

Contributions

Jordi Gartner publishes this work through Beedbyte.

AI assistance

Methods: AI tools assisted with developing the construction, formalizing and checking the proof, and comparing earlier sources; the Lean 4.34.0 formalization verifies the stated theorem.

References

  1. Fixed-k47 versioned source package, commit-pinned
  2. Fixed-k47 package README, commit-pinned
  3. English fixed-k47 research note, commit-pinned
  4. German draft translation, commit-pinned
  5. Simplified Chinese draft translation, commit-pinned
  6. Lean theorem source K47Full.lean, commit-pinned
  7. Fixed-k47 package checksum index, commit-pinned
  8. Fixed-k47 copied-source replay pins, commit-pinned
  9. Luiz, Campos, and Richter, IC-17-12 (2017), path lemmas and Theorem 14: P95 and P95 with one center leaf.
  10. Bahls, Lake, and Wertheim, Gracefulness of families of spiders (2010), Theorem 1 and proof.
  11. Shan and Zhong, Graceful Labeling of Two Families of Spiders, Lemma 1 (classical alpha-amalgamation).

Version history

VersionPublishedChange note
v1Proves that every actual vertex of S(47^n,1^m) can be the unique zero in a graceful labeling for n ≥ 2 and m ≥ 0.

Cite this version

Beedbyte. Zero-rotatability for spiders with 47-edge arms. Beedbyte, v1, 2026-10-10.

https://beedbyte.tech/publications/zero-rotatability-47-edge-arm-spiders/v/1

SHA-256 — Version85df0aad9524ecf2b03fd90b67f199496aa6c5b29bf92fab42c826663e5b0cac

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