Homotopy-coherent algebra via Segal conditions

Many homotopy-coherent algebraic structures can be described by Segal-type limit conditions determined by an “algebraic pattern”, by which we mean an ∞-category equipped with a factorization system and a collection of “elementary” objects. Examples of structures that occur as such “Segal O-spaces” for an algebraic pattern Oinclude ∞-categories, (∞, n)-categories, ∞-operads (including symmetric, non-symmetric, cyclic, and modular ones), ∞-properads, and algebras for a (symmetric) ∞-operad in spaces.In the first part of this paper we set up a general framework for algebraic patterns and their associated Segal objects, in-cluding conditions under which the latter are preserved by left and right Kan extensions. In particular, we obtain necessary and sufficient conditions on a pattern Ofor free Segal O-spaces to be described by an explicit colimit formula, in which case we say that Ois “extendable”. In the second part of the paper we explore the relationship be-tween extendable algebraic patterns and polynomial monads, by which we mean cartesian monads on presheaf ∞-categories that are accessible and preserve weakly contractible limits. We first show that the free Segal O-space monad for an extendable pattern Ois always polynomial. Next, we prove an ∞-categorical version of Weber’s Nerve Theorem for polynomial monads, and use this to define a canonical extendable pattern from any polynomial monad, whose Segal spaces are equivalent to the algebras of the monad. These constructions yield functors between polynomial monads and extendable algebraic patterns, and we show that these exhibit full sub-categories of “saturated” algebraic patterns and “complete” polynomial monads as localizations, and moreover restrict to an equivalence between the ∞-categories of saturated patterns and complete polynomial monads

On a spectral sequence for the cohomology of infinite loop spaces

We study the mod-2 cohomology spectral sequence arising from delooping the Bousfield-Kan cosimplicial space giving the 2-nilpotent completion of a connective spectrum X. Under good conditions its E₂-term is computable as certain nonabelian derived functors evaluated at H* (X) as a module over the Steenrod algebra, and it converges to the cohomology of Ω ∞ X. We provide general methods for computing the E₂-term, including the construction of a multiplicative spectral sequence of Serre type for cofibration sequences of simplicial commutative algebras. Some simple examples are also considered; in particular, we show that the spectral sequence collapses at E₂ when X is a suspension spectrum

Derived coisotropic structures II: stacks and quantization

We extend results about $n$-shifted coisotropic structures from part I of this work to the setting of derived Artin stacks. We show that an intersection of coisotropic morphisms carries a Poisson structure of shift one less. We also compare non-degenerate shifted coisotropic structures and shifted Lagrangian structures and show that there is a natural equivalence between the two spaces in agreement with the classical result. Finally, we define quantizations of $n$-shifted coisotropic structures and show that they exist for $n>1$.Comment: 45 pages. Contains the second half of arXiv:1608.01482v1 with new material adde