Seminars in Pure Mathematics
Please see also the new pure maths seminar page.
2016-2017 Leicester Pure Mathematics Seminar (Semester 2)
31/01/2017 Jelena Grbic (Southampton) "Homotopy theory of toric objects"
Abstract: At the beginning of this millennium, Toric Topology has been recognised as a new branch of Topology closely related to Algebraic Geometry, Combinatorics and Algebra. Initially problems of Toric Topology were motivated by the study of toric geometry. The approach I take departs from geometry and brings in the tools and techniques of homotopy theory. That allows one to generalise the fundamental concepts of Toric Topology to new ones which will further have applications to geometric group theory, robotics and applied mathematics.
07/02/2017 Melanie Rupflin (Oxford) "Minimal surfaces and geometric flows"
Abstract: The classical Plateau problems has been one of the most influential problems in the development of modern analysis. Posed initially by Lagrange, it asks whether a closed curve in Euclidean space always spans a surfaces with minimal possible area, a question that was answered positively by Douglas and Rado around 1930. In this talk I want to consider some aspects of the classical Plateau Problem and its generalisations and discuss furthermore how one can "flow" to such minimal surfaces by following a suitably defined gradient flow of the Dirichlet energy, i.e. of the integral of gradient squared.
14/02/2017 Muneerah Saad Al Nuwairan (King Faisal University) "The additivity problem"
Abstract: In our talk, we present the well- known problem in the field of quantum information theory known as “The additivity problem”. It concerns transferring classical information using quantum channels. We will build a mathematical model for the problem, and show that the field of Representation theory provides rich source for solutions. We will also introduce EPOSIC channels, a class of SU(2)-covariant quantum channels that form the extreme points of all SU(2)-irreducibly covariant channels. These channels provide us with a potential solution for the problem.
Change of day and time: Wednesday 3pm 22/02/2017 Sebastian del Baño (Queen Mary London) "Gaussian distributions on affine spaces"
Abstract: We present intrinsic variants of some classical results on real and p-adic Gaussian distributions. Results such as the Isserles-Wick formula for higher moments are considerably simplified by using an intrinsic tensorial approach.
28/02/2017 Ilke Canakci (Durham) "Infinite rank surface cluster algebras"
Abstract: Cluster algebras were introduced by Fomin and Zelevinsky in the context of Lie theory in 2002, however they received much attention since many applications in diverse areas of mathematics have been discovered including quiver representations, Teichmuller theory, integrable systems and string theory. An important class of cluster algebras, called surface cluster algebras, were introduced by Fomin, Shapiro and Thurston by associating cluster algebra structure to triangulated marked surfaces. I will review the state of the art in research associated to surface cluster algebras and report on joint work with Anna Felikson where we introduce a generalisation of surface cluster algebras to infinite rank by associating cluster algebras to surfaces with finitely many accumulation points of boundary marked points.
07/03/2017 Nathan Broomhead (Plymouth) "Thick subcategories, arc-collections and mutation"
Abstract: I will explain some work, in which I describe the lattices of thick subcategories of discrete derived categories. This is done using certain collections of exceptional and sphere-like objects related to non-crossing configurations of arcs in a geometric model.
14/03/2017 Tom Bridgeland (Sheffield) Title TBA
21/03/2017 Justin Lynd (Aberdeen) Title TBA
02/05/2017 Joao Faria Martins (Leeds) Title TBA
09/05/2017 Sarah Zerbes (UCL) Title TBA
Extra session: Monday 22/05/2017 Yann Palu (LAMFA, France) Title TBA
2016-2017 Leicester Pure Mathematics Seminar (Semester 1)
04/10/2016 Giuseppe Tinaglia (King's College, London) The geometry of constant mean curvature surfaces in Euclidean space
Abstract: In this talk I will begin by reviewing classical geometric properties of constant mean curvature surfaces, H>0, in R^3. I will then talk about several more recent results for surfaces embedded in R^3 with constant mean curvature, such as curvature and radius estimates for simply-connected surfaces embedded in R^3 with constant mean curvature. Finally I will show applications of such estimates including a characterisation of the round sphere as the only simply-connected surface embedded in R^3 with constant mean curvature and area estimates for compact surfaces embedded in a flat torus with constant mean curvature and finite genus. This is joint work with Meeks.
11/10/2016 Artie Prendergast-Smith (Loughborough) Cones of positive classes
Abstract: I will explain why convex cones of "positive" cohomology classes arise naturally in algebraic geometry, why they are important, and some things we know about them.
18/10/2016 Simon Willerton (Sheffield) The magnitude of odd balls (From category theory to potential theory)
Abstract: Tom Leinster defined the notion of the magnitude of a finite metric space, which is some notion of size, using his idea of Euler characteristic of a finite category. You can extend this notion to nice infinite metric spaces such as subsets of Euclidean space. Tom and I conjectured a formula for the magnitude of a convex body involving classical invariants such as volume and surface area, but it turned out to be difficult to calculate precisely for non-trivial bodies. I will explain all of this and how Tony Carbery and Juan-Antonio Barceló recently used potential theory to calculate the magnitude of odd dimensional balls.
Thursday 20/10/2016 Extra seminar: Neil Ghani (Strathclyde) Compositional Game Theory
Abstract: The central concept of economic game theory is that of Nash Equilibria consisting of a collection of strategies for each player in a game such that no player has a reason to change their strategy assuming all players keep their strategies the same. This talk reports on a new categorical foundation for economic game theory - compositional game theory (CGT). At its core, CGT involves a new representation of games where large games are built from smaller subcomponents of the game. However, while natural from a categorical perspective, developing CGT is no simple matter, eg all current models of game theory are inherently non-compositional! More fundamentally, not all reasoning can be put in the compositional form, especially if there is significant emergent behaviour present in a system which is not present in its subsystems. And, this is certainly the norm in game theory, eg an optimal strategy for a game may not remain optimal when that game is part of a larger network of games.
8/11/2016 Bob Coecke (Oxford) From quantum foundations to natural language meaning via diagrams
Abstract: This talk concerns how mathematical structures immersing in one discipline can be relevant in an entirely different discipline. The conceptual focus is on structures that enable one to describe interaction. Earlier work on an entirely diagrammatic formulation of quantum theory, which is soon to appear in the form of a textbook , has somewhat surprisingly guided us towards an answer for the following question [2, 3]: how do we produce the meaning of a sentence given that we understand the meaning of its words? This work has practical applications in the area of natural language processing, and the resulting tools have meanwhile outperformed existing methods. Recent developments involve the use of several more concepts from quantum theory, for example, density matrices for modelling ambiguity  and lexical entailment , and convex state spaces to model interaction of psychological concepts .
NB: this talk doesn’t require any background in quantum theory, nor in linguistics, nor in category theory
 B. Coecke & A. Kissinger (2016, 850 pages) Picturing Quantum Processes. A first course on quantum theory and diagrammatic reasoning. Cambridge University Press.
 B. Coecke, M. Sadrzadeh & S. Clark (2010) Mathematical foundations for a compositional distributional model of meaning. arXiv:1003.4394
 S. Clark, S., B. Coecke, E. Grefenstette, S. Pulman & M. Sadrzadeh (2013) A quantum teleportation inspired algorithm produces sentence meaning from word meaning and grammatical structure. arXiv:1305.0556.
 R. Piedeleu, D. Kartsaklis, B. Coecke & M. Sadrzadeh (2015) Open System Categorical Quantum Semantics in Natural Language Processing. arXiv:1502.00831
 D. Bankova, B. Coecke, M. Lewis & D. Marsden (2015): Graded Entailment for Compositional Distributional Semantics. arXiv:1601.04908
 J. Bolt, B. Coecke, F. Genovese, M. Lewis, D. Marsden & R. Piedeleu (2016) Interacting Conceptual Spaces. SLPCS. arXiv:1608.01402
15/11/2016 Giuseppe Tinaglia (King's College, London) The geometry of constant mean curvature surfaces in Euclidean space
(This talk was postponed from 4 October, see above)
22/11/2016 Brita Nucinkis (Royal Holloway) Classifying spaces for families and their finiteness conditions
Abstract: I will give a survey on cohomological finiteness conditions for classifying spaces for families of subgroups, such as the dimension or the type and will discuss some old and new questions.
29/11/2016 Markus Linckelmann (City) When do derivations on an algebra yield a simple Lie algebra?
Abstract: A derivation on an algebra A is a linear endomorphism which satisfies the product rule. The quotient of the space of derivations by the subspace of inner derivations is the first Hochschild cohomology of the algebra A. This is a Lie algebra - and if A is defined over a field of prime characteristic p, then this is a p-restricted Lie algebra. Motivated by questions arising in modular representation theory, we investigate connections between the algebra structure of A and the Lie algebra structure of its first Hochschild cohomology. What are the implications for A if its first Hochschild cohomology is a simple Lie algebra? In joint work with Lleonard Rubio y Degrassi, we answer this question for block algebras of finite groups with one simple module.
13/12/2016 Peter Jorgensen (Newcastle) Thick subcategories of d-abelian categories (report on joint work with Martin Herschend and Laertis Vaso)
Abstract:Let d be a positive integer. The notion of d-abelian categories was introduced by Jasso. Such a category does not have kernels and cokernels, but rather d-kernels and d-cokernels which are longer complexes with weaker universal properties. Canonical examples of d-abelian categories are d-cluster tilting subcategories of abelian categories. We introduce the notion of thick subcategories of d-abelian categories and show a classification of the thick subcategories of a family of d-abelian categories associated to quivers of type A_n. If time permits, we show how thick subcategories are in bijective correspondence with a particularly nice class of algebra epimorphisms. This generalises a classic result by Geigle and Lenzing.
2015-2016 Leicester Pure Mathematics Seminar (Semester 2)
26/01/2016 Alison Parker (Leeds) Some central idempotents for the Brauer Algebra (abstract)
09/02/2016 Sian Fryer (Leeds) There And Back Again: A Localization's Tale (abstract)
16/02/2016 Radha Kessar (City) Ratonality properties for blocks of finite groups (abstract)
23/02/2016 Michael Whittaker (Glasgow) New directions in self-similar group theory (abstract)
01/03/2016 Alexander Kasprzyk (Nottingham ) Mirror Symmetry for del Pezzo surfaces (abstract)
08/03/2016 Stefan Kolb (Newcastle) Universal K-matrix for coideal subalgebras (abstract)
Thursday 24/03/2016 at 11am Mark Weber (Macquarie) Vines and internal algebras (abstract)
Wednesday 20/04/2016 at 1:30pm Ilke Canakci (Durham) Snake graphs, cluster algebras and continued fractions (abstract)
26/04/2016 Jing Ping Wang (Kent) Symbolic representation and classification of integrable equations (abstract)
03/05/2016 Dmitri Gourevich (Valenciennes) Quantum matrix algebras and braided Yangians (abstract)
10/05/2016 Martin Kalck (Edinburgh) Matrix factorisations: Knörrer’s periodicity and beyond (abstract)
2015-2016 Leicester Pure Mathematics Seminar (Semester 1)
25/08/2015 Maria Ronco (Universidad de Talca) A regular operad on Dyck paths (abstract)
22/09/2015 Christine Vespa (Université de Strasbourg) Stable homology of automorphism groups of free groups and functor homology (abstract)
3pm: James Waldron (Newcastle University) Lie algebroids and differentiable stacks (abstract)
13/10/2015 Szymon Dolecki (Université de Bourgogne) Convergence, compactness, completeness (abstract)
20/10/2015 André Neves (Imperial College London) Morse index and Geometry (abstract)
27/10/2015 Ana Rovi (Newcastle University) Lie algebroids in the Loday-Pirashvili category (abstract)
03/11/2015 TBA () TBA (abstract)
10/11/2015 Petter Bergh (NTNU, Trondheim) n-angulated categories (abstract)
17/11/2015 Sira Gratz (Leibniz Universität Hannover) Torsion pairs in discrete cluster categories of Dynkin type A (abstract)
24/11/2015 Sinead Lyle (University of East Anglia) Semigroup algebras and standard bases (abstract)
01/12/2015 TBA () (abstract)
08/12/2015 Ian McIntosh (University of York) Minimal surfaces and their Higgs bundles (abstract)
2014-15 Leicester Pure Mathematics Seminar – Semester 2
03/02/2015 Peter Topping (University of Warwick) The harmonic map flow revisited abstract
10/02/2015 Constanze Roitzheim (University of Kent) Model categories- the joy of abstract nonsense abstract
17/02/2015 Joanne Leader (University of Leicester) Finite Generation of Ext and (D, A)-stacked Algebras abstract
24/02/2015 Jan Boronski (IT4 Innovations, Ostrava) On Birkhoff Attractors and Rotational Chaos abstract
03/03/2015 Manolis Georgoulis (University of Leicester) Adaptive numerical methods for the approximation of dynamic singularities abstract
10/03/2015 Jamie Vicary (University of Oxford) Higher categories and quantum computation abstract
17/03/2015 Michael Singer (University College London) A new approach to monopole metrics abstract
24/03/2015 Imma Galvez (Universitat Politecnica de Catalunya)
Incidence (co)algebras and decomposition spaces abstract
5/05/2015 Francisco Martin (University of Granada) abstract
Translating solitons of the mean curvature flow
12/05/2015 Nicola Gambino (University of Leeds) abstract
Commutative 2-algebra and analytic functors
2014-15 Leicester Pure Mathematics Seminar – Semester 1
28/08/2014 Julie Bergner (Univ. of California at Riverside), Homotopical higher categories (Abstract)
30/09/2014 Henri Anciaux (Univ. of San Paulo) Marginally trapped submanifolds (Abstract)
7/10/2014 Gavin Brown (Loughborough University), Pfaffian ideals and Calabi-Yau 3-folds (Abstract)
14/10/2014 Andrey Lazarev (Lancaster University) Koszul-Morita duality (Abstract)
21/10/2014 Stephane Launois (Univ. of Kent) Efficient recognition of totally nonnegative cells (Abstract)
28/10/2014 Samuel Petite (Univ. de Picardie) Simplicity of the homeomorphism group of a tilable lamination (Abstract)
4/11/2014 Magdalena Rodriguez (Univ. of Granada) Minimal surfaces with finite total curvature and related problems (Abstract)
11/11/2014 Mike Prest (Univ. of Manchester) Ziegler spectra of domestic string algebras (Abstract)
18/11/2014 Pavel Tumarkin (Durham Univ.) Coxeter groups, cluster algebras, and geometric manifolds (Abstract)
25/11/2014 Ivan Tyukin (University of Leicester) Lyapunov method for unstable attractors (Abstract)
2/12/2014 13:30-14:30 Rosie Laking (University of Manchester)
Morphisms in Kb(proj ˄) for ˄ a gentle algebra. (Abstract)
15:00-16:00 Joeri Van der Veken (University of Leuven)
Sequences of harmonic maps in the 3-sphere (Abstract)
9/12/2014 Jamie Walton (Univ. of York)
Patch frequencies for cut-and-project sets and Diophantine approximation (Abstract)
2013-14 Leicester Pure Mathematics Seminar – Semester 2
28/01/2014 Ines Henriques (Sheffield), F-thresholds and Test ideals for determinantal ideals of maximal minors (Abstract)
04/02/2014 Ralf Schiffler (Conneticut), Positivity in Cluster Algebras (Abstract)
11/02/2014 Bruce Bartlett (Oxford), Bordism representation theory in dimension 3 (Abstract)
18/02/2014 Jean Fasel (Muenchen), Homotopy groups of algebraic spheres and classification of vector bundles (Abstract)
25/02/2014 David Pauksztello (Manchester), An introduction to discrete derived categories (Abstracts)
04/03/2014 Ben Sharp (Imperial), Global estimates for harmonic maps form surfaces (Abstract)
- 1:30 pm Ian McIntosh (York), Minimal surfaces and complex quasi-Fuchsian groups (Abstract)
- 3 pm Osbaldo Mata Gutierrez (CIMAT, Guanajuato),Subvarieties of the moduli space of vector bundles on a curve (Abstract)
18/03/2014 Karin Erdmann (Oxford), On the generalized Auslander-Reiten condition (Abstract)
25/03/2014 Anthony Manning (Warwick) A map of the tetrahedron that describes the sequence of pedal triangles (Abstract)
06/05/2014 Michael Farber (Warwick), Large Random Spaces and Groups.
2013-14 Leicester Pure Mathematics Seminar – Semester 1
1/10/2013 Anna Felikson (Durham) Cluster algebras of finite mutation type (Abstract)
08/10/2013 Jan Grabowski (Lancaster) Gradings on cluster algebras and associated combinatorics (Abstract)
15/10/2013 Joseph Grant (Leeds) Braid group actions and a theorem of Rouquier and Zimmermann (Abstract)
22/10/2013 Behrang Noohi (Queen Mary) String operations for orbifolds (Abstract)
29/10/2013 Ilke Canakci (Leicester) Surface cluster algebra combinatorics via snake graphs(Abstract)
5/11/2013 Lynn Heller (Tuebingen) Constrained Willmore Hopf Tori (Abstract)
12/11/2013 Toby Hall (Liverpool) Digit frequencies for expansions in non-integer bases.(Abstract)
19/11/2013 Mark Grant (Newcastle) Lower bounds for the topological complexity of groups(Abstract)
26/11/2013 Alan Robinson (Warwick) Products and homotopy (Abstract)
3/12/2013 Tom Sutherland (Sheffield) Mutation and quadratic differentials (Abstract)
10/12/2013 Francis Burstall (Bath), Geometry and dynamics of isothermic submanifolds(Abstract)