The cotangent complex and Thom spectra


Abstract in English

The cotangent complex of a map of commutative rings is a central object in deformation theory. Since the 1990s, it has been generalized to the homotopical setting of $E_infty$-ring spectra in various ways. In this work we first establish, in the context of $infty$-categories and using Goodwillies calculus of functors, that various definitions of the cotangent complex of a map of $E_infty$-ring spectra that exist in the literature are equivalent. We then turn our attention to a specific example. Let $R$ be an $E_infty$-ring spectrum and $mathrm{Pic}(R)$ denote its Picard $E_infty$-group. Let $Mf$ denote the Thom $E_infty$-$R$-algebra of a map of $E_infty$-groups $f:Gto mathrm{Pic}(R)$; examples of $Mf$ are given by various flavors of cobordism spectra. We prove that the cotangent complex of $Rto Mf$ is equivalent to the smash product of $Mf$ and the connective spectrum associated to $G$.

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