An unknotting theorem for delta and sharp edge‐homotopy |
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Authors: | Ryo Nikkuni |
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Affiliation: | Department of Mathematics, Faculty of Education, Kanazawa University, Kakuma‐machi, Kanazawa, Ishikawa, 920‐1192, Japan |
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Abstract: | Two spatial embeddings of a graph are said to be delta (resp. sharp) edge‐homotopic if they are transformed into each other by self delta (resp. sharp) moves and ambient isotopies. We show that any two spatial embeddings of a graph are delta (resp. sharp) edge‐homotopic if and only if the graph does not contain a subgraph which is homeomorphic to the theta graph or the disjoint union of two 1‐spheres, or equivalently G is homeomorphic to a bouquet. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) |
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Keywords: | Spatial graph delta move sharp move Ck ‐move |
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