Embedding calculus and Vassiliev spectral sequence

Fuente: arXiv
Saved in:
Bibliographic Details
Main Author: Moriya, Syunji
Format: Preprint
Published: 2025
Subjects:
Online Access:
Tags: Add Tag
No Tags, Be the first to tag this record!
_version_ 1866918163588841472
author Moriya, Syunji
author_facet Moriya, Syunji
contents Vassiliev spectral sequence and Sinha spectral sequence are both related to cohomology of the space of long knots $\mathbb{R}\to \mathbb{R}^3$. Although they have different origins, the Vassiliev $E_1$-page and the Sinha $E_2$-page are isomorphic (up to a degree shift). In this paper, we prove that they have isomorphic $E_\infty$-pages if the coefficient ring is a field. Together with degeneracy of the Sinha sequence, this implies that the Vassiliev sequence degenerates at $E_1$-page over $\mathbb{Q}$ including the non-diagonal part. Our result also implies that for any coefficient field, the space of finite type $n$ knot invariants is isomorphic to the space of weight systems of weight $\leq n$ if and only if the parts of the Sinha sequence of bidegree $(-i,i)$ degenerate at $E_2$ for $i\leq 2n$. For the construction of the isomorphism, we use a variant of Thom space model which was introduced in the author's previous paper and captures embedding calculus of the knot space in terms of fat diagonals. As a byproduct of the construction, we give a partial computation on differentials of unstable versions of the Vassiliev sequence which converge to finite dimensional approximations of the knot space.
format Preprint
id arxiv_https___arxiv_org_abs_2509_23766
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Embedding calculus and Vassiliev spectral sequence
Moriya, Syunji
Algebraic Topology
Geometric Topology
55R80, 57R40, 55U10
Vassiliev spectral sequence and Sinha spectral sequence are both related to cohomology of the space of long knots $\mathbb{R}\to \mathbb{R}^3$. Although they have different origins, the Vassiliev $E_1$-page and the Sinha $E_2$-page are isomorphic (up to a degree shift). In this paper, we prove that they have isomorphic $E_\infty$-pages if the coefficient ring is a field. Together with degeneracy of the Sinha sequence, this implies that the Vassiliev sequence degenerates at $E_1$-page over $\mathbb{Q}$ including the non-diagonal part. Our result also implies that for any coefficient field, the space of finite type $n$ knot invariants is isomorphic to the space of weight systems of weight $\leq n$ if and only if the parts of the Sinha sequence of bidegree $(-i,i)$ degenerate at $E_2$ for $i\leq 2n$. For the construction of the isomorphism, we use a variant of Thom space model which was introduced in the author's previous paper and captures embedding calculus of the knot space in terms of fat diagonals. As a byproduct of the construction, we give a partial computation on differentials of unstable versions of the Vassiliev sequence which converge to finite dimensional approximations of the knot space.
title Embedding calculus and Vassiliev spectral sequence
topic Algebraic Topology
Geometric Topology
55R80, 57R40, 55U10
url https://arxiv.org/abs/2509.23766