### Abstract

We develop a calculus for diagrams of knotted objects. We define arrow presentations, which encode the crossing information of a diagram into arrows in a way somewhat similar to Gauss diagrams, and more generally w–tree presentations, which can be seen as “higher-order Gauss diagrams”. This arrow calculus is used to develop an analogue of Habiro’s clasper theory for welded knotted objects, which contain classical link diagrams as a subset. This provides a “realization” of Polyak’s algebra of arrow diagrams at the welded level, and leads to a characterization of finitetype invariants of welded knots and long knots. As a corollary, we recover several topological results due to Habiro and Shima and to Watanabe on knotted surfaces in 4–space. We also classify welded string links up to homotopy, thus recovering a result of the first author with Audoux, Bellingeri and Wagner.

Original language | English |
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Pages (from-to) | 397-456 |

Number of pages | 60 |

Journal | Algebraic and Geometric Topology |

Volume | 19 |

Issue number | 1 |

DOIs | |

Publication status | Published - 2019 Feb 6 |

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### ASJC Scopus subject areas

- Geometry and Topology

### Cite this

*Algebraic and Geometric Topology*,

*19*(1), 397-456. https://doi.org/10.2140/agt.2019.19.397

**Arrow calculus for welded and classical links.** / Meilhan, Jean Baptiste; Yasuhara, Akira.

Research output: Contribution to journal › Article

*Algebraic and Geometric Topology*, vol. 19, no. 1, pp. 397-456. https://doi.org/10.2140/agt.2019.19.397

}

TY - JOUR

T1 - Arrow calculus for welded and classical links

AU - Meilhan, Jean Baptiste

AU - Yasuhara, Akira

PY - 2019/2/6

Y1 - 2019/2/6

N2 - We develop a calculus for diagrams of knotted objects. We define arrow presentations, which encode the crossing information of a diagram into arrows in a way somewhat similar to Gauss diagrams, and more generally w–tree presentations, which can be seen as “higher-order Gauss diagrams”. This arrow calculus is used to develop an analogue of Habiro’s clasper theory for welded knotted objects, which contain classical link diagrams as a subset. This provides a “realization” of Polyak’s algebra of arrow diagrams at the welded level, and leads to a characterization of finitetype invariants of welded knots and long knots. As a corollary, we recover several topological results due to Habiro and Shima and to Watanabe on knotted surfaces in 4–space. We also classify welded string links up to homotopy, thus recovering a result of the first author with Audoux, Bellingeri and Wagner.

AB - We develop a calculus for diagrams of knotted objects. We define arrow presentations, which encode the crossing information of a diagram into arrows in a way somewhat similar to Gauss diagrams, and more generally w–tree presentations, which can be seen as “higher-order Gauss diagrams”. This arrow calculus is used to develop an analogue of Habiro’s clasper theory for welded knotted objects, which contain classical link diagrams as a subset. This provides a “realization” of Polyak’s algebra of arrow diagrams at the welded level, and leads to a characterization of finitetype invariants of welded knots and long knots. As a corollary, we recover several topological results due to Habiro and Shima and to Watanabe on knotted surfaces in 4–space. We also classify welded string links up to homotopy, thus recovering a result of the first author with Audoux, Bellingeri and Wagner.

UR - http://www.scopus.com/inward/record.url?scp=85062853989&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85062853989&partnerID=8YFLogxK

U2 - 10.2140/agt.2019.19.397

DO - 10.2140/agt.2019.19.397

M3 - Article

VL - 19

SP - 397

EP - 456

JO - Algebraic and Geometric Topology

JF - Algebraic and Geometric Topology

SN - 1472-2747

IS - 1

ER -