Zigzags and free adjunctions
We construct an explicit combinatorial model of the functor which adds right adjoints to the morphisms of an $\infty$-category, and we speculate on possible extensions to higher dimensions.
math.CT↗
arXiv subjects
Lorenzo Riva
Publications and source records attributed to Lorenzo Riva.
Higher tensor categories and their extensions: notes from the Scottish Talbot On Algebra and Topology
These lecture notes are the product of a week-long learning workshop on the work of Johnson-Freyd and Reutter on the problem of the existence of minimal nondegenerate extensions of braided fusion categories (arXiv:2105.15167). They recount the mathematical arguments of the original paper from an expository angle, with background material covering the algebra and homotopy theory required to understand the statement and follow the proof. The notes are aimed at newcomers to the field of (braided) fusion 1- and 2-categories.
math.QA↗
Higher categories of push-pull spans, II: Matrix factorizations
This is the second part of a project aimed at formalizing Rozansky-Witten models in the functorial field theory framework. In the first part we constructed a symmetric monoidal $(\infty, 3)$-category $\mathscr{CRW}$ of commutative Rozansky-Witten models with the goal of approximating the $3$-category of Kapustin and Rozansky. In this paper we extend work of Brunner, Carqueville, Fragkos, and Roggenkamp on the affine Rozansky-Witten models: we exhibit a functor connecting their $2$-category of matrix factorizations with the homotopy $2$-category of $\mathscr{CRW}$, and calculate the associated TFTs.
math.CT↗
Higher categories of push-pull spans, I: Construction and applications
This is the first part of a project aimed at formalizing Rozansky-Witten models in the functorial field theory framework. Motivated by work of Calaque-Haugseng-Scheimbauer, we construct a family of symmetric monoidal $(\infty,3)$-categories parametrized by an $\infty$-category with finite limits and a functor into symmetric monoidal $\infty$-categories, such that the functor admits pushforwards. This $(\infty,3)$-category contains correspondences in the base $\infty$-category equipped with local systems, which compose via a push-pull formula. We apply this general construction to provide an approximation to the $3$-category of Rozansky-Witten models whose existence was conjectured by Kapustin-Rozansky-Saulina; this approximation behaves like a "commutative" version of the conjectured $3$-category and is related to work of Stefanich on higher quasicoherent sheaves.
math.CT↗
Low regularity of non-$L^2(R^n)$ local solutions to gMHD-alpha systems
The Magneto-Hydrodynamic (MHD) system of equations governs viscous fluids subject to a magnetic field and is derived via a coupling of the Navier-Stokes equations and Maxwell's equations. Recently it has become common to study generalizations of fluids-based differential equations. Here we consider the generalized Magneto-Hydrodynamic alpha (gMHD-$α$) system, which differs from the original MHD system by including an additional non-linear terms (indexed by $α$), and replacing the Laplace operators by more general Fourier multipliers with symbols of the form $-|ξ|^γ/ g(|ξ|)$. In a paper by Pennington, the problem was considered with initial data in the Sobolev space $H^{s,2}(\mathbb{R}^n)$ with $n \geq 3$. Here we consider the problem with initial data in $H^{s,p}(\mathbb{R}^n)$ with $n \geq 3$ and $p > 2$. Our goal is to minimize the regularity required for obtaining uniqueness of a solution.
math.AP↗