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On the minimality of pancake decomposition of surface germs

Metric Geometry 2025-06-02 v1 Algebraic Geometry

Abstract

The abnormal surfaces called snakes and circular snakes, defined in \cite{GabrielovSouza}, are special types of surface germs capturing the outer Lipschitz phenomena relevant to the outer classification problem. We provide algorithms to obtain a minimal pancake decomposition, i.e., where the number of pancakes is minimal, for snakes and circular snakes. We call a pancake decomposition obtained from our algorithm a greedy pancake decomposition. We also prove that greedy pancake decompositions of weakly outer Lipschitz equivalent snakes (or circular snakes) are weakly equivalent, in the sense that there is a weakly outer bi-Lipschitz homeomorphism between the surfaces mapping each greedy pancake to a greedy pancake. This implies that such minimal decompositions are also canonical up to weakly outer bi-Lipschitz equivalence.

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Cite

@article{arxiv.2505.23976,
  title  = {On the minimality of pancake decomposition of surface germs},
  author = {Davi Lopes Medeiros and Euripedes Carvalho da Silva and Emanoel Souza},
  journal= {arXiv preprint arXiv:2505.23976},
  year   = {2025}
}

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21 pages