Publications / prescribed-zero-window-equal-arm-spiders

An extended zero-label interval for equal-arm spiders

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For k=23+24t, n≥2 and m≥0, every selected named long-arm vertex at depth 17+20t through 20+22t can be zero in its own graceful labeling for every integer t≥0. For t≥1, the same holds at the additional depth 21+22t.

For every integer t≥0, let k=23+24t. For all n≥2 and m≥0, each selected named long-arm vertex of S(k^n,1^m) at a depth d with 17+20t≤d≤20+22t can be assigned zero in a graceful labeling. When t≥1, this also holds at depth d=21+22t. A separate labeling may be used for each chosen arm and depth.

The q24 B2 and B4 constructions give the existing interval. A terminal B1 adapter reverses a neighboring zero pair while preserving the midpoint alpha condition, adding the adjacent depth 21+22t for t≥1. The path labels transfer to the selected arm of the actual spider, and a residual construction completes the labeling on the other arms and the original center leaves. At t=0, the statement remains the previously established k=23 case.

Endpoint-matched alpha-path concatenation is established machinery: Hicks–Ollis–Schmitt use it in the proof of Lemma 4.5, and Adamaszek gives the reversed gluing in Lemma 1. Earlier path cases also cover n=2,m=0 and n=2,m=1, as reported by Luiz, Campos, and Richter.

Statements & evidence

Q24-VARIABLE-WINDOW-ACTUAL-SPIDER Proof provided

For every integer t≥0, k=23+24t, n≥2 and m≥0, every selected named long-arm vertex of the actual spider S(k^n,1^m) at any integer depth d with 17+20t≤d≤20+22t has a graceful labeling assigning zero to that vertex. For t≥1, the same holds at d=21+22t. The labeling may depend on the selected arm and depth.

Formal verification
Formally verified within the stated scope
Review status
Internal check
Evidence
The terminal adapter extends the q24 interval by the additional depth 21+22t for every t≥1. The frozen author formalization and a separate copied-source replay were checked with Lean 4.34.0; the versioned source package will contain the theorem and reproducibility records.
Scope
For integer t≥0, k=23+24t, n≥2 and m≥0. The prior depths are all integers in [17+20t,20+22t]; for t≥1 the added depth is 21+22t. Each selected named long-arm vertex is treated separately and may have its own graceful labeling. No other depths or vertex classes are asserted.
Assumptions
S(k^n,1^m) is the finite spider with n named arms of k edges and m original unit leaves at the center. Graceful means a bijection from vertices to 0..|E| whose edge absolute differences biject to 1..|E|.
Toolchain
Lean 4.34.0; the terminal author source and separate copied-source replay each compiled 34 modules. Standard Lean kernel verification.
Reviewer
Formal and literature checks are internal project checks only; no external or peer review is claimed. Worldwide priority of the exact positional result remains unknown.

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 B2/B4 constructions and terminal adapter, checking finite label and edge-sum inventories, and building the Lean formalization. The theorem and a separate copied source were checked with Lean 4.34.0.

References

  1. Hicks–Ollis–Schmitt, proof of Lemma 4.5 (endpoint-matched alpha-path concatenation).
  2. Adamaszek, Efficient Enumeration of Graceful Permutations, Lemma 1 (reversed endpoint gluing).
  3. Luiz, Campos, and Richter, report IC-17-12, Lemma 4 and Theorem 14 (path cases).
  4. Shan and Zhong, Graceful Labeling of Two Families of Spiders, Lemma 1 (classical alpha-amalgamation).
  5. Beedbyte, q24 variable-window v1 source and prior interval theorem (commit 94889aa8916282eba53288760fced7b6677dade8).
  6. Beedbyte, q24 terminal B1 source package (commit 9f92eeefaf8cc57a7d04446b20e66bd169848e3b).
  7. Terminal q24 theorem source, Q24Terminal.lean.
  8. Separate copied-source Lean replay evidence.

Version history

VersionPublishedChange note
v3Adds the terminal q48 zero-labeling at depth 22+22t for t≥2. For t≥5, its union with the q24/D8 prefix gives the derived contiguous depth range 1≤d≤22+22t.
v2Adds the terminal q24 construction, giving zero labelings at depth 21+22t for every t≥1.
v1Proves that for k=23+24t, every named long arm has a separately zero-labelable vertex at each depth from 17+20t through 20+22t, for all t≥0, n≥2 and m≥0.

Cite this version

Beedbyte. An extended zero-label interval for equal-arm spiders. Beedbyte, v2, 2026-10-10.

https://beedbyte.tech/publications/prescribed-zero-window-equal-arm-spiders/v/2

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