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Higher Barbell Diffeomorphisms and Watanabe's Clasper Surgery
Abstract
Watanabe constructed many nontrivial family diffeomorphisms in π*Diff∂(D4), which were obtained by doing clasper surgeries on trivalent graphs. In this paper, we generalize the barbell diffeomorphism discovered by Budney and Gabai and construct a series of nontrivial elements in πk−1Diff∂(Mk+1') with Mk+1'=naturalk+1 S2× D2 the (k+1)-cuff barbell, which we call higher barbell diffeomorphisms. We show that Watanabe's constructions can be realized as implanted higher barbell diffeomorphisms in D4 if the trivalent graph is homologically nonzero in the graph complex. Combining this realization with Watanabe's detection theorem, we establish the nontriviality of these implanted higher barbell diffeomorphisms.
Related
BibTeX
@misc{tan2026higher,
title = {{Higher Barbell Diffeomorphisms and Watanabe's Clasper Surgery}},
author = {Xiayu Tan},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.24697},
eprint = {2609.24697},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.24697},
note = {CC BY-NC-ND 4.0},
}
RIS
TY - UNPB
TI - Higher Barbell Diffeomorphisms and Watanabe's Clasper Surgery
AU - Xiayu Tan
PY - 2026
DA - 2026/09/21
PB - arXiv
DO - 10.48550/arxiv.2609.24697
UR - https://arxiv.org/abs/2609.24697
AB - Watanabe constructed many nontrivial family diffeomorphisms in π_*Diff_∂(D^4), which were obtained by doing clasper surgeries on trivalent graphs. In this paper, we generalize the barbell diffeomorphism discovered by Budney and Gabai and construct a series of nontrivial elements in π_k−1Diff_∂(M_k+1') with M_k+1'=natural_k+1 S^2× D^2 the (k+1)-cuff barbell, which we call higher barbell diffeomorphisms. We show that Watanabe's constructions can be realized as implanted higher barbell diffeomorphisms in D^4 if the trivalent graph is homologically nonzero in the graph complex. Combining this realization with Watanabe's detection theorem, we establish the nontriviality of these implanted higher barbell diffeomorphisms.
ER -