Two second Steenrod squares for odd Khovanov homology

Dirk Schuetz

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arXiv · 2209.00389

Two second Steenrod squares for odd Khovanov homology

Dirk Schuetz

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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 $\mathbb{Z}/2\mathbb{Z}$ 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 $s$-invariant with $\mathbb{Z}/2\mathbb{Z}$ coefficients. We expect it to be related to the second Steenrod square arising from the Sarkar-Scaduto-Stoffregen construction.

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Dirk Schuetz. 2022-09-01. Two second Steenrod squares for odd Khovanov homology. https://arxiv.org/abs/2209.00389

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