Paul WedrichHamburg University | UHH · Department of Mathematics
Paul Wedrich
PhD
About
40
Publications
1,436
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Introduction
I am a mathematician working on bridges between low-dimensional topology and representation theory. Two focus points of my research have been the development of functorial homology theories for knots and links, and the exploration of their deep connections to (higher) representation theory and mathematical physics. I also enjoy applying topological and combinatorial tools to solve problems in representation theory.
Additional affiliations
October 2017 - September 2019
January 2016 - June 2016
Position
- Research Associate
Education
October 2012 - October 2015
October 2011 - June 2012
October 2008 - July 2011
Publications
Publications (40)
We introduce a multiparameter deformation of the triply‐graded Khovanov–Rozansky homology of links colored by one‐column Young diagrams, generalizing the “‐ified” link homology of Gorsky–Hogancamp and work of Cautis–Lauda–Sussan. For each link component, the natural set of deformation parameters corresponds to interpolation coordinates on the Hilbe...
Using the non-semisimple Temperley–Lieb calculus, we study the additive and monoidal structure of the category of tilting modules for SL2\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \...
We describe the universal target of annular Khovanov–Rozansky link homology functors as the homotopy category of a free symmetric monoidal linear category generated by one object and one endomorphism. This categorifies the ring of symmetric functions and admits categorical analogues of plethystic transformations, which we use to characterize the an...
We construct a Kirby color in the setting of Khovanov homology: an ind-object of the annular Bar-Natan category that is equipped with a natural handle slide isomorphism. Via functoriality/cabling properties of Khovanov homology, we define a Kirby-colored Khovanov homology that is invariant under the handle slide Kirby move, up to isomorphism. The c...
The skein lasagna module is an extension of Khovanov-Rozansky homology to the setting of a four-manifold and a link in its boundary. This invariant plays the role of the Hilbert space of an associated fully extended (4+epsilon)-dimensional TQFT. We give a general procedure for expressing the skein lasagna module in terms of a handle decomposition f...
We introduce a multi-parameter deformation of the triply-graded Khovanov--Rozansky homology of links colored by one-column Young diagrams, generalizing the "$y$-ified" link homology of Gorsky--Hogancamp and work of Cautis--Lauda--Sussan. For each link component, the natural set of deformation parameters corresponds to interpolation coordinates on t...
We study the skein relation that governs the HOMFLYPT invariant of links colored by one-column Young diagrams. Our main result is a categorification of this colored skein relation. This takes the form of a homotopy equivalence between two one-sided twisted complexes constructed from Rickard complexes of singular Soergel bimodules associated to brai...
Using diagrammatic methods, we define a quiver with relations depending on a prime p \mathsf {p} and show that the associated path algebra describes the category of tilting modules for S L 2 \mathrm {SL}_{2} in characteristic p \mathsf {p} . Along the way we obtain a presentation for morphisms between p \mathsf {p} -Jones–Wenzl projectors.
Using the non-semisimple Temperley-Lieb calculus, we study the additive and monoidal structure of the category of tilting modules for $\mathrm{SL}_{2}$ in the mixed case. This simultaneously generalizes the semisimple situation, the case of the complex quantum group at a root of unity, and the algebraic group case in positive characteristic. We des...
We study two kinds of categorical traces of (monoidal) dg categories, with particular interest in categories of Soergel bimodules. First, we explicitly compute the usual Hochschild homology, or derived vertical trace, of the category of Soergel bimodules in arbitrary types. Secondly, we introduce the notion of derived horizontal trace of a monoidal...
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 \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...
In this note, we compute the centers of the categories of tilting modules for G = SL 2 in prime characteristic, of tilting modules for the corresponding quantum group at a complex root of unity, and of projective G g T -modules when g = 1, 2.
The Blanchet link homology theory is an oriented model of Khovanov homology, functorial over the integers with respect to link cobordisms. We formulate a stable homotopy refinement of the Blanchet theory, based on a comparison of the Blanchet and Khovanov chain complexes associated to link diagrams. The construction of the stable homotopy type reli...
The Hamiltonian of the N -state superintegrable chiral Potts (SICP) model is written in terms of a coupled algebra defined by N − 1 types of Temperley–Lieb generators. This generalises a previous result for N = 3 obtained by Fjelstad and Månsson (2012 J. Phys. A: Math. Theor. 45 155208). A pictorial representation of a related coupled algebra is gi...
The hamiltonian of the $N$-state superintegrable chiral Potts (SICP) model is written in terms of a coupled algebra defined by $N-1$ types of Temperley-Lieb generators. This generalises a previous result for $N=3$ obtained by J. F. Fjelstad and T. M\r{a}nsson [J. Phys. A {\bf 45} (2012) 155208]. A pictorial representation of this coupled algebra is...
We prove that the generating functions for the one row/column colored HOMFLY-PT invariants of arborescent links are specializations of the generating functions of the motivic Donaldson-Thomas invariants of appropriate quivers that we naturally associate with these links. Our approach extends the previously established tangles-quivers correspondence...
In this note we compute the centers of the categories of tilting modules for G=SL2 in prime characteristic, of tilting modules for the corresponding quantum group at a complex root of unity, and of projective GgT-modules when g=1,2.
We study two kinds of categorical traces of (monoidal) dg categories, with particular interest in categories of Soergel bimodules. First, we explicitly compute the usual Hochschild homology, or derived vertical trace, of the category of Soergel bimodules in arbitrary types. We show that this dg algebra is formal, and calculate its homology explicit...
We use Khovanov-Rozansky gl(N) link homology to define pivotal 4-categories, which give rise to invariants of oriented smooth 4-manifolds. The technical heart of this construction is a proof of the sweep-around property, which makes these link homologies well defined in the 3-sphere and implies pivotality for the associated 4-categories.
Using diagrammatic methods, we define a quiver algebra depending on a prime p and show that it is the algebra underlying the category of tilting modules for SL(2) in characteristic p. Along the way we obtain a presentation for morphisms between p-Jones-Wenzl projectors.
We describe the universal target of annular Khovanov-Rozansky link homology functors as the homotopy category of a free symmetric monoidal category generated by one object and one endomorphism. This categorifies the ring of symmetric functions and admits categorical analogues of plethystic transformations, which we use to characterize the annular i...
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 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 gl(2) fo...
In previous work, we have constructed diagrammatic idempotents in an affine extension of the Temperley-Lieb category, which describe extremal weight projectors for sl(2), and which categorify Chebyshev polynomials of the first kind. In this paper, we generalize the construction of extremal weight projectors to the case of gl(N) for N greater than o...
We prove that the generating functions for the colored HOMFLY-PT polynomials of rational links are specializations of the generating functions of the motivic Donaldson-Thomas invariants of appropriate quivers that we naturally associate with these links. This shows that the conjectural links-quivers correspondence of Kucharski-Reineke-Sto\v{s}i\'c-...
Abstract: I will talk about recent progress in understanding the structure of type A link homologies. This includes the definition of integral, equivariant, colored sl(N) Khovanov-Rozansky link homologies, which are functorial under link cobordisms, as well as a study of their deformations and stability properties. I will finish by discussing some...
We prove that the bigraded colored Khovanov-Rozansky type A link and tangle invariants are functorial with respect to link and tangle cobordisms.
We introduce a quotient of the affine Temperley-Lieb category that encodes all weight-preserving linear maps between finite-dimensional sl(2)-representations. We study the diagrammatic idempotents that correspond to projections onto extremal weight spaces and find that they satisfy similar properties as Jones-Wenzl projectors, and that they categor...
Abstract: I will start by introducing the family of colored Khovanov-Rozansky sl(N) and HOMFLY-PT link homologies, which categorify the Reshetikhin-Turaev sl(N) link invariants and their large N limits. The members of this large family of invariants are related through spectral sequences from which additional topological information can be extracte...
We use categorical skew Howe duality to find recursion rules that compute
categorified sl(N) invariants of rational tangles colored by exterior powers of
the standard representation. Further, we offer a geometric interpretation of
these rules which suggests a connection to Floer theory. Along the way we make
progress towards two conjectures about t...
We define reduced colored sl(N) link homologies and use deformation spectral sequences to characterize their dependence on color and rank. We then define reduced colored HOMFLY-PT homologies and prove that they arise as large N limits of sl(N) homologies. Together, these results allow proofs of many aspects of the physically conjectured structure o...
Abstract: I will start by explaining how deformations help to answer two important questions about the family of (colored) sl(N) link homology theories: What geometric information about links do they contain? What relations exist between them? I will recall Lee’s deformation of Khovanov homology and sketch how it generalizes to the case of colored...
We use super
q-Howe duality to provide diagrammatic presentations of an
idempotented form of the Hecke algebra and of categories of
glN-modules (and, more generally,
gl(N|M)-modules) whose objects are tensor generated by exterior and symmetric powers of the
vector representations. As an application, we give a representation theoretic explanation a...
We generalize results of Lee, Gornik and Wu on the structure of deformed
colored sl(N) link homologies to the case of non-generic deformations. To this
end, we use foam technology to give a completely combinatorial construction of
Wu's deformed colored sl(N) link homologies. By studying the underlying
deformed higher representation theoretic struct...
We compute q-holonomic formulas for the HOMFLY polynomials of 2-bridge links
colored with one-column (or one-row) Young diagrams.