PreprintCC BY 4.0arXiv
Bar cohomology of links: beyond Milnor invariants
Abstract
We develop bar cohomology of link complements as an invariant of links in homology spheres. In this setting, bar cohomology is a Hopf algebra which is calculable using surfaces and their intersection curves in a link complement. In this first in a sequence of works, we introduce the invariant and show that it defines a canonical subspace of the tensor Hopf algebra, which already encodes information about Milnor's link invariants and provides geometrically significant information beyond them.
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BibTeX
@misc{friedman2026cohomology,
title = {{Bar cohomology of links: beyond Milnor invariants}},
author = {Greg Friedman and Nir Gadish and Robin Koytcheff and Dev Sinha and Ben Walter},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2609.11009},
eprint = {2609.11009},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.11009},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Bar cohomology of links: beyond Milnor invariants
AU - Greg Friedman
AU - Nir Gadish
AU - Robin Koytcheff
AU - Dev Sinha
AU - Ben Walter
PY - 2026
DA - 2026/10/15
PB - arXiv
DO - 10.48550/arxiv.2609.11009
UR - https://arxiv.org/abs/2609.11009
AB - We develop bar cohomology of link complements as an invariant of links in homology spheres. In this setting, bar cohomology is a Hopf algebra which is calculable using surfaces and their intersection curves in a link complement. In this first in a sequence of works, we introduce the invariant and show that it defines a canonical subspace of the tensor Hopf algebra, which already encodes information about Milnor's link invariants and provides geometrically significant information beyond them.
ER -