Khovanov homology and categorification of skein modules

  • Hoel Queffelec

    Université de Montpellier, France
  • Paul Wedrich

    Max-Planck-Institut für Mathematik, Bonn, Germany and Australian National University, Canberra, Australia
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For every oriented surface of finite type, we construct a functorial Khovanov homology for links in a thickening of the surface, which takes values in a categorification of the corresponding gl2\mathfrak {gl}_2 skein module. The latter is a mild refinement of the Kauffman bracket skein algebra, and its categorification is constructed using a category of gl2\mathfrak {gl}_2 foams that admits an interesting non-negative grading. We expect that the natural algebra structure on the gl2\mathfrak {gl}_2 skein module can be categorified by a tensor product that makes the surface link homology functor monoidal. We construct a candidate bifunctor on the target category and conjecture that it extends to a monoidal structure. This would give rise to a canonical basis of the associated gl2\mathfrak {gl}_2 skein algebra and verify an analogue of a positivity conjecture of Fock and Goncharov and Thurston. We provide evidence towards the monoidality conjecture by checking several instances of a categorified Frohman–Gelca formula for the skein algebra of the torus. Finally, we recover a variant of the Asaeda–Przytycki–Sikora surface link homologies and prove that surface embeddings give rise to spectral sequences between them.

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Hoel Queffelec, Paul Wedrich, Khovanov homology and categorification of skein modules. Quantum Topol. 12 (2021), no. 1, pp. 129–209

DOI 10.4171/QT/148