English

Two second Steenrod squares for odd Khovanov homology

Geometric Topology 2025-10-03 v2 Algebraic Topology

Abstract

Recently, Sarkar-Scaduto-Stoffregen constructed a stable homotopy type for odd Khovanov homology, hence obtaining an action of the Steenrod algebra on Khovanov homology with Z/2Z\mathbb{Z}/2\mathbb{Z} coefficients. Motivated by their construction we propose a way to compute the second Steenrod square. Our construction is not unique, but we can show it to be a link invariant which gives rise to a refinement of the Rasmussen ss-invariant with Z/2Z\mathbb{Z}/2\mathbb{Z} coefficients. We expect it to be related to the second Steenrod square arising from the Sarkar-Scaduto-Stoffregen construction.

Keywords

Cite

@article{arxiv.2209.00389,
  title  = {Two second Steenrod squares for odd Khovanov homology},
  author = {Dirk Schuetz},
  journal= {arXiv preprint arXiv:2209.00389},
  year   = {2025}
}

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36 pages