Thammasat University
"Ola Bratteli"
Mathematical Physics Seminar
Mathematics in Thailand Colloquium
Dedicated to the memory of Ola Bratteli

Seminar's sessions are informally organized once or twice every month at the Department of Mathematics and Statistics in Thammasat University Rangsit Campus.

The format of the gatherings comprise a one-two hours academic seminar, followed by one-two hours of discussion forum that can be followed by a dinner.

The topics covered by the Mathematical Physics Seminar are mainly (but not exclusively) related to: operator algebras, non-commutative geometry, mathematical physics, quantum theory, differential geometry, category theory, philosophy/history of physics/mathematics and occasionally other general science areas.

The Mathematics in Thailand Colloquium aims to showcase some of the best mathematicians and scientists in Thailand, inviting young active researchers (but occasionally senior academics) that, through direct discussion, can inspire and widen the perspectives of graduate students and faculty members alike.

For information please contact: Paolo Bertozzini

The seminar is partially supported by Thammasat University Research Grant 2/15/2556 "Categorical Non-commutative Geometry". 

Forthcoming Meetings

To Be Announced - Room LC2-230 - Time: 15.00-18.30 - Mathematics in Thailand Colloquium 

Tirasan Khandhawit - Okinawa Institute of Science and Technology - Japan 
Title: To Be Announced [slides - to be uploaded]

To Be Announced 

To Be Announced (January 2019) - Room LC2-230 - Time: 15.00-18.30
- Mathematics in Thailand Colloquium 

David Yost - Federation University - Ballarat - Australia 
Title: To Be Announced [slides - to be uploaded]

To Be Announced 

To Be Rescheduled - Room LC2-230 - Time: 15.00-18.30 - Mathematics in Thailand Colloquium 

Anna Kamińska
- University of Memphis - USA
Title: Geometric Properties of Noncommutative Symmetric Spaces of Measurable Operators and Unitary Matrix Ideals [slides - to be uploaded]

This is a survey lecture presenting a number of geometric properties of non-commutative symmetric spaces of measurable operators E(M, τ) and unitary matrix ideals CE, where M is a von Neumann algebra with a semi-finite, faithful and normal trace τ, and E is a (quasi) Banach function space and a sequence lattice, respectively. We provide auxiliary definitions, notions, examples and we discuss a number of properties that are most often used in studies of local and global geometry of (quasi) Banach spaces. We interpret the general spaces E(M, τ) in the case when E=Lp obtaining Lp(M, τ) spaces, and in the case when E is a sequence space we explain how the unitary matrix space CE can be in fact identified with the symmetric space of measurable operators G(M, τ) for some Banach function lattice G. We present the results on (complex) extreme points, (complex) strict convexity, strong extreme points and midpoint local uniform convexity, k-extreme points and k-convexity, (complex or local) uniform convexity, smoothness and strong smoothness, (strongly) exposed points, (uniform) Kadec-Klee properties, Banach-Saks properties, Radon-Nikodym property and stability in the sense of Krivine-Maurey. We also present some open problems.

Previous Meetings

Tuesday 04 December 2018 - Room LC2-230 - Time: 15.00-18.30
Mathematics in Thailand Colloquium

Robert Egrot - Mahidol University  - Thailand
Title: Canonicity in Algebra and Logic [slides]

This talk is intended to be an introductory survey of the broad area of algebraic logic, a subject sitting neatly in the intersection of classical mathematics, computer science and philosophy. This survey will necessarily be light on both technical details and coverage, but I hope to convey at least a sense of the big ideas involved. The focus will be the algebraic/order theoretic notion of a canonical extension, its history, and its role in the theory of non-classical logics. The aim of the talk is to build up to a rough understanding of the sentence "canonical extensions provide completeness results for substructural logics with respect to relational semantics". 

Friday 30 November 2018 - Room LC2-230 - Time: 15.00-18.30 - Mathematical Physics Seminar  

Watthanan Jatuviriyapornchai - Mahidol University - Thailand 
Title: Derivation of Mean-field Equations for Stochastic Particle Systems [slides]

We study the single site dynamics in stochastic particle systems of misanthrope type with bounded rates on a complete graph. In the limit of diverging system size we establish convergence to a Markovian non-linear birth death chain, described by a mean-field equation known also from exchange-driven growth processes. Conservation of mass in the particle system leads to conservation of the first moment for the limit dynamics, and to non-uniqueness of stationary measures. The proof is based on a coupling to branching processes via the graphical construction, and establishing uniqueness of the solution for the limit dynamics. As particularly interesting examples we discuss the dynamics of two models that exhibit a condensation transition and their connection to exchange-driven growth processes. 

Tuesday 27 November - Room LC2-230 - Time: 15.00-16.30 - Mathematics in Thailand Colloquium 

Chee Yap - Courant Institute - New York University - USA
Isolating Simple Roots of Zero-Dimensional Real Systems [slides]

We describe a new algorithm for isolating simple real roots of a zero-dimensional system of equations within a box region. The equations need not be polynomial. Our subdivision-based algorithm is effective in that it provides explicit precision requirements to justify a rigorous implementation. This is aided by the use of 3 levels of abstraction of our algorithmic primitives.
The main predicate is the Moore-Kostelides (MK) test, based on the Miranda Theorem (1940). Although the MK test is well-known in interval community, to our knowledge, it has not been synthesized into a complete global algorithm.  Our algorithm uses two other predicates: an exclusion and a Jacobian test.
We provide a complexity analysis of our algorithm based on intrinsic geometric parameters.
(Joint Work with Juan Xu). 

Friday 16 November - Room LC2-230 - Time: 09.00-12.00 - Mathematics in Thailand Colloquium 

Pichet Chaoha - Chulalongkorn University  - Thailand
Title: Virtual Stability and Fixed Point Sets [slides]

Virtual stability is a useful concept in relating the fixed point set of a selfmap on a Hausdorff space to its convergence set. In this talk, we will present the motivation and the development of virtual stability. Recent results and some applications will be also discussed. 

Friday 09  November 2018 - Room LC2-230 - Time: 15.00-18.30 - Mathematics in Thailand Colloquium   

Prof. Dmitry Feichtner-Kozlov - University of Bremen - Germany
Title: An Invitation to Applied Topology [slides]

Applied Topology is a modern and dynamic research field in Mathematics, which combines theoretical rigour, combinatorial complexity, and focus on applications both in other fields in mathematics, as well as in other sciences. In this talk we give a gentle introduction to the topic by focusing our attention on two aspects: connections between Discrete Mathematics and Applied Topology, and applications to the Theoretical Computer Science, specifically to Distributed Computing.

Monday 22 October 2018 - Room LC2-230 - Time: 15.00-18.30 - Mathematics in Thailand Colloquium 

Keng Wiboontan - Chulalongkorn University  - Thailand
Title: Linear Representations of a Gyrogroup and Möbius's Functional Equation [slides]

In this talk, at the beginning I will give an introduction to the gyrogroup structure first proposed by Abraham A.Ungar in 1988. At first, the gyrogroup structure was used to describe an algebraic structure hidden inside Einstein's velocity addition in special relativity. A gyrogroup encodes a group-like structure but it lacks the usual associative law. In stead, any gyrogroup has the so-called gyroassociative law. This law reflects the intricate structure in Einstein's velocity addition. The two main examples of gyrogroups are the Einstein gyrogroup and the Möbius gyrogroup. Many algebraic properties of gyrogroups have bee studied extensively. Recently, Teerapong Suksumran gave a definition of gyrogroup actions. I will present a joint work with him where we define linear representations of a gyrogroup and then obtain some analogous results as those of representations of a group. Then to find concrete examples of irreducible representations of the Möbius gyrogroup, one need to solve the so-called Möbius's functional equation. 

Monday 08  October 2018 - Room LC2-230 - Time: 15.00-18.30 - Mathematical Physics Seminar  

Sujin Suwanna - Mahidol University (Optical and Quantum Physics Laboratory, Department of Physics) - Thailand
Title: Dynamics of Open Quantum Systems and Decoherence Feedback Control [slides - to be uploaded]

In closed quantum systems, dynamics of quantum states are described by one-parameter strongly continuous unitary groups, where the Hamiltonian corresponding to the Schrödinger or the Liouville-von Neumann equation is a generator of the unitary groups, acting on a Hilbert space of square-integrable functions. In open quantum systems, where interaction with environment is essential, so decoherence is induced, the dynamics are described instead by semigroups. Several types of dynamical maps are possible depending on the nature of the environment and the interaction. In this talk, we will discuss the Lindblad dynamical maps and the Markovian environment. We will show that under some reasonable physically-motivated assumptions, the dynamical map can be decomposed into a unitary component corresponding to a reversible process, and a semigroup corresponding to an irreversible process, hence the entropy change. When the environment is assumed to be Markovian, the Ito's and Stratonovich's stochastic master equations can be derived. If an open quantum system sacrifices part of its subsystem to probe the environmental response, a feedback control is possible to cancel the decoherence.  This gives rise to potential of fidelity control in open quantum systems for purposes of quantum computing and information processing. Keywords: dynamical maps, open quantum systems, stochastic master equation, decoherence.

Monday 10 September 2018 - Room LC2-230 - Time: 15.00-18.30 - Mathematical Physics Seminar

Mairi Sakellariadou - King's College - London - UK 
Title: Aspects of the Bosonic Spectral Action for Almost Commutative Manifolds [slides - to be uploaded]

I will review the noncommutative spectral geometry, a gravitational model that combines noncommutative geometry with the spectral action principle, in an attempt to unify General Relativity and the Standard Model of electroweak and strong interactions. I will briefly present phenomenological consequences, address some open questions and discuss the gravitational sector of the theory.

Mairi Sakellariadou - King's College - London - UK 
Title: Noncommutative Gravity with Self-dual Variables [slides - to be uploaded]

I will present a noncommutative extension of Palatini-Holst theory on a twist-deformed spacetime. The twist deformation entails an enlargement of the gauge group, and leads to the introduction of new gravitational degrees of freedom. In particular, the tetrad degrees of freedom must be doubled, thus leading to a bitetrad theory of gravity. I will study the commutative limit of the model, focusing in particular on the role of torsion and non-metricity. I will briefly comment on connections with bimetric theories and the role of local conformal invariance in the commutative limit. 

Monday 20 August - Room LC2-230 - Time: 15.00-18.30 - Mathematics in Thailand Colloquium

Wayne Lawton - Siberian Federal University - Krasnoyarks - Russia
Title: Fourier Representation of Polynomial Ideals [slides]

Given a polynomial ideal I in n variables we let R(I) denote the vector space of functions f on the rank n lattice such that PF = 0 for all P in I. Here F denotes the formal power series with coefficients f. We prove that a function f is in R(I) iff it equals the complex Fourier transform of a distribution D supported on the variety V(I) and Pf = 0. This characterized the multiplicity variety associated with I. Our proof develops a new fibered method to lift analytic functionals and our result extends those of Ehrenpreis, Hormander, Malgrange and Palmadorov that represent solutions of certain partial differential equations by complex Fourier transforms. We suggest potential extensions to ideals in Weyl algebras.

4-15 August 2018 - "Ola Bratteli" Workshop on Operator Algebras

14 August 2018 - Room LC2-230 - Time: 10.00-12.30 - Workshop on Operator Algebras 
Saeid Zahmatkesh - KMUTT - Bangkok - Thailand
Title: C*-algebras [slides]
The aim of this talk is to give a quick introduction on the theory of C*-algebras. 

14 August 2018 - Room LC2-230 - Time: 14.00-16.00 - Workshop on Operator Algebras 
David Evans - Cardiff University  - UK
Title: Subfactor and K-theory approaches to Conformal Field Theory [canceled for health issues] 
Abstract: I will discuss some of the tools and results to understand conformal field theories and their modular invariant partition functions, modular tensor categories and module categories via subfactor theory in operator algebras and twisted equivariant K-theory.

14 August 2018 - Room LC2-230 - Time: 14.00-16.00 - Workshop on Operator Algebras 
Paolo Bertozzini - Thammasat University - Bangkok - Thailand
Title: Spectra for Non-commutative Unital C*-algebras [slides - to be uploaded]
We outline a still tentative new attempt (developed in collaboration with Roberto Conti and Natee Pitiwan) to obtain a non-commutative generalization of the well-known Gel'fand-Naumark duality (between compact Hausdorff topological spaces and  commutative unital C*-algebras), where "geometric spectra" for unital non-commutative C*-algebras can be described (among several alternatives) via "non-commutative spaceoids": suitable uniform bundles of saturated uniform Fell-line bundles over pair groupoids, equipped with a transition amplitude structure, satisfying certain saturation and uniformity conditions.

15 August 2018 - Room LC2-230 - Time: 10.00-12.30 - Workshop on Operator Algebras 
Saeid Zahmatkesh - KMUTT - Bangkok - Thailand

Title: The Nica-Toeplitz Algebras of Abelian Lattice Ordered Groups as Full Corners in Group Crossed Products [slides]
The notion of quasi-lattice (nonabelian) ordered groups was introduced by Nica in 1992. Since then several mathematicians (operator algebraists) have been studying the C*-algebras corresponding to the semigroup C*-dynamical systems associated with such partially ordered groups. The aim of this talk (research) is to show that the Nica-Toeplitz algebra (of abelian lattice ordered groups) introduced by Fowler in 2002 is related to group crossed product C*-algebras as full corner. By such relation, we could import many information on the structure of Nica-Toeplitz algebra from the well-established theory of crossed products by groups.

15 August 2018 - Room LC2-230 - Time: 14.00-16.00 - Workshop on Operator Algebras 
Saeid Zahmatkesh - KMUTT - Bangkok - Thailand

Title: Introduction to C*-dynamical Systems and Crossed Products

Monday 09 April 2018 - Room LC2-230 - Time: 15.00-18.30 - Mathematics in Thailand Colloquium

Thotsaporn Thanatipanonda
- Mahidol University International College - Bangkok
Title: Moment Method on Ramsey Numbers [slides
] [notes