Abstract: You can see the abstract of this talk in pdf format here.

Matrix polynomial problem (Photos)

Abstract: You can see the abstract of this talk in pdf format here.

Abstract: Ideal Approximation Theory (developed jointly with X. Fu, P .A. Guil Asension and B .J . Torrecillas) is the study of complete ideal cotorsion pairs (I,J) in an exact theory (A,E). In this talk, I will try to give a summary of the key aspects of ideal approximation theory, beginning with a review of the motivating results and arguments from the classical approximation theory.

On the decimal expansion of e, the Golden Ratio, and log(2016/2105) (Photos)

Abstract: It is commonly expected that e, log 2, root 2, among other « classical » numbers behave, in many respects, like almost all numbers. For instance, their decimal expansion should contain every finite block of digits from {0, ..., 9}. We are very far away from establishing such a strong assertion. However, there has been some recent progress, and it is now possible to prove that the decimal expansion of e, log(2016/2015) and of any irrational algebraic number cannot be `too simple', in a suitable sense.

Alireza Nasr-Isfahani
University of Isfahan and IPM
January 13, 2016 (23th Dey 1394) at 15:00-16:00

Abstract: You can see the abstract of this talk in pdf format here.

The Internet of Things – The Ultimate ICT Revolution (Photos)

Joseph Sifakis
Turing Award 2007, Professor at EPFL
January 9, 2016 (19th Dey 1394) at 14:00-15:00

Abstract: The Internet of Things (IoT) is a vision born from the convergence between embedded and networking technologies. It refers to the interconnection of uniquely identifiable embedded computing devices within the existing Internet infrastructure. Things can refer to a wide variety of devices such as heart monitoring implants, biochip transponders, automobiles with built-in sensors, field operation devices, smart thermostat and home appliances. They are equipped with sensors, actuators and microcontrollers which can provide the “real-time” embedded processing that is a key requirement of most IoT applications. The collected data are made available through a unified networking infrastructure, to users and interconnected machines. Furthermore, they can be processed and analyzed by the cloud for decision-making in order to respond to changes quickly and accurately, to predict events and optimize resources. We shortly discuss the IoT vision and its feasibility. We show that its achievement challenges our capacity to design mixed hardware-software systems that are trustworthy and optimal. We advocate the need for rigorous system design techniques. We present the current state of the art and discuss three major scientific problems: 1) linking physicality and computation; 2) component-based systems engineering; 3) intelligence in particular as the ability of system adaptation in order to meet given requirements in the presence of uncertainty.   Achieving the IoT vision will have a tremendous societal, technological and scientific impact. In particular, it will reinvigorate Computing and enrich the discipline with new scientific foundations.

The geometry and analysis of black holes space-times in general relativity (Photos)

Mihalis Dafermos
Princeton University
Decmber 31, 2015 (10th Dey 1394) at 10:00-11:00

Holomorphic functions on the 3-dimensional Euclidean space  and the 3-valent  tree

Abdelghani Zeghib
CNRS, Ecole Normale Supérieure de Lyon, France
Decmber 20, 2015 (29th Azar 1394) at 14:00-15:00

Abstract: We introduce a natural notion of holomorphy for complex valued functions defined on various spaces such as the Euclidean space of dimension 3 and the simplicial tree of valency 3. This concept is related to harmonicity and coincides in some cases with existent notions  of discrete holomorphy. We precise the framework and show connections with classical concepts in Riemannian geometry. We bring out a rigidity phenomenon of holomorphic functions in comparison with harmonic ones. In the later case, one has a Dirichlet problem which allows one to reconstructed  the function from its values at infinity. In contrast,  holomorphic function are recovered, from initial data, by means of a holomorphic random dynamical system.

Mathematics and democracy

Vladimir S. Matveev
Friedrich-Schiller-Universität Jena, Germany
Decmber 20, 2015 (29th Azar 1394) at 15:30-16:30

Abstract: This talk is for general audience, elementary enough to be understood by a student or by a good pupil in a high school; it is based on certain results of  Plott (1967), McKelvey (1976), and on the survey paper of A. Slinko (1991). I will suggest a visual natural geometric model of a parliament and prove by methods of elementary geometry that this model leads to quite unpleasant consequences. I will discuss with you the practical hints how to avoid these consequences.

Sheaf Semantics and Limit Structures (Photos)  

Andrés Villaveces
Universidad Nacional de Colombia, Colombia
Decmber 3, 2015 (12th Azar 1394) at 11:00-12:00

Abstract: I will explain the construction of model theory on sheaves: the motivation, earlier results and recent applications to number theory and mathematical physics.

Reciprocity Laws and Equidistribution Laws

Chandan Dalawat
Harish-Chandra Research Institute, Allahabad, India
September 26, 2015 (4th Mehr 1394) at 16:00-17:00

Abstract: Reciprocity Laws and Equidistribution Laws occupy a central position in Number Theory.Beginning with the work of Fermat, Euler and Gauss, they gave rise to Class Field Theory, of which the Langlands Programme is a vast generalisation. Recent major advances like the proof of Fermat's Last Theorem are some of the spectacular applications of these theories.  In this talk, which is meant for a general audience, we will give an elementary introduction to these ideas.

Cohen-Montgomery duality for bimodules and its application to stable equivalences of Morita type (Photos)

Hideto Asashiba
Shizuoka University, Japan
September 21, 2015 (30th Shahrivar 1394) at 16:00-17:00

Abstract: You can see the abstract of this talk in pdf format here.

Market consistent and sub-consistent valuations in incomplete markets (Photos)

Hirbod Assa
University of Liverpool
August 20, 2015 (29th Mordad 1394) at 11:00-12:00

Abstract: From January 2016, all insurance companies that are regulated within Solvency II framework will have to value their asset and liabilities using a market-consistent method. This paper studies market-consistent and sub-consistent valuations in incomplete financial markets with two types (type I and II) of market consistency. While market consistency of type I holds under fairly weak assumptions, the type II consistency, which is the usual definition of market consistency in the literature, holds only if the market prices are linear for fully hedged assets. We also characterize the market consistent and sub-consistent evaluators in several different ways. We discuss how market-consistent and sub-consistent valuations can be regarded as a robust approach to hedging and pricing in the presence of market imperfections such as market incompleteness and frictions.

Jonathan James Wylie
University of Hong Kong
July 30, 2015 (8th Mordad 1394) at 11:00-12:00

Abstract: We consider a family of cumulative-sum change-point estimators for detecting a change in some moment of a correlated sequence. We show that the 1/n convergence rate typical of the independent case is also achieved for short-memory and long-memory sequences. Moreover, since cumulative-sum estimators compare differences between empirical means, it seems natural that ergodicity is a minimal assumption for consistent change-point estimation. Surprisingly, we show that change-point estimation can be consistently performed for nonergodic sequences. We determine the rate of convergence for sequences under very general conditions including nonergodic cases. In particular, we determine the rate of convergence for sequences in which the correlations decay to zero arbitrarily slowly or even do not decay to zero at all.

John Anderson
Royal Institute of Technology, Sweden
May 23, 2015 (2ed Khordad 1394) at 16:00-17:00

Abstract: The most classical free boundary problem is the obstacle problem. The obstacle problem consists of a minimization problem with a one sided constraint. That is we try to minimize, say, the Dirichlet energy among all functions u(x) that satisfy the constraint u(x)\ge \psi(x) in the domain. It is well known that the minimizers are "as regular as the obstacle" if the obstacle is of regularity class up to C^{1,1}. But from a potential theoretic perspective it is also interesting to consider the Euler-Lagrange equations without the constraint u(x)\ge \psi(x). For this problem the regularity theory becomes much more subtle and the classical result was only recently proved. In this talk I will describe the problem and the idea behind the solution. I will do my best to make the talk at a level that is accessible for a wide audience. This is a joint work with E. Lindgren and H. Shahgholian.

Hayk Mikayelyan
Xi'an Jiaotong-Liverpool University, China
May 25, 2015 (4th Khordad 1394) at 16:00-17:00

Abstract: A rearrangement problem related to a free boundary problem will be presented. The optimal solution is a 3-value function, which makes the application of the standard rearrangement theory techniques impossible. Some open problems will be presented. This is an ongoing joint project with Behrouz Emamizadeh.

Edwin van Dam
Tilburg University, The Netherlands
May 5, 2015 (15 th Ordibehesht 1394) at 14:00-15:00

Abstract: The eigenvalues of the adjacency matrix of a graph contain a lot --- but not always all --- information on the structure of the graph. In this talk, we will dive deeper into graphs that have a lot of combinatorial symmetry: distance-regular graphs (such as Hamming graphs and Johnson graphs). We will give an overview of when distance-regularity is determined by the eigenvalues (and when it is not). We will see how systems of orthogonal polynomials can help to recognize distance-regular graphs from their eigenvalues and a little extra information through the `spectral excess theorem'. We then discuss how these methods and ideas led to the construction of the twisted Grassmann graphs, a family of distance-regular graphs that have the same spectrum as certain Grassmann graphs. These twisted graphs are currently the only known family of distance-regular graphs with unbounded diameter that are not vertex-transitive. If time permits, we also present some more recent results, such as a characterization of the generalized odd graphs ('the odd-girth theorem'), and discuss some results on graphs that are `almost distance-regular', in particular how the latter can be used to construct non-isomorphic graphs with the same eigenvalues.

Kai Hauser
Technical University of Berlin
March 8, 2015 (17 th Esfand 1393) at 14:00-15:00

Abstract: Recent developments in computer programming, information technology, and robotics have given rise to optimistic predictions about future possibilities in artificial intelligence. In this talk I will present two sets of philosophical arguments that cast this optimism into doubt. One of them suggests that there is a limitation of principle applying to any machine whatsoever. The lecture is aimed at a general audience and does not presuppose any special expertise in computer science, philosophy or mathematical logic.

Reza Rezaeian Farashahi
Isfahan University of Technology and IPM
February 19, 2015 (30 th Bahman 1393) at 11:00-12:00

Abstract: The number of isomorphism classes of various types of elliptic curves over finite fields has attracted interest. We give explicit formulas for the number of distinct elliptic curves over a finite field, up to isomorphism,  in several families of curves of cryptographic interest.

Ali Golmakani
Federal University of Alagoas, Brazil
January 5, 2015 (15 th Day 1393) at 16:00-17:30

Abstract: In this talk we start by giving some preliminary definitions in dynamical systems and specially different types of orbits. Then we review some classical and recent results in the real quadratic family. We also give a very short proof of the positiveness of measure of the set of parameters which leads to stochastic dynamic. Finally, we discuss the probability of being stochastic in the real quadratic family.

Hadi Salmasian
University of Ottawa
January 4, 2015 (14 th Day 1393) at 11:00-12:00 

Abstract: The algebra of invariant differential operators on a multiplicity-free representation of a reductive group has a concrete basis, usually referred to as the Capelli basis. The spectrum of the Capelli basis on spherical representations results in a family of symmetric polynomials (after ρ-shift) which has been studied extensively by Knop and Sahi since the early 90's. In this talk , we generalize some of the Knop- Sahi results to the symmetric superpair GL(m,2n)/OSp(m,2n). As a side result, we show that the qualitative Capelli problem (in the sense of Howe-Umeda) for this superpair has an affirmative answer. This talk is based on an ongoing project with Siddhartha Sahi.

Mehdi Tatari
Isfahan University of Technology and IPM
January 1, 2015 (11th Day 1393) at 11:00-12:00

Abstract: Convection diffusion problems appear in the flow of most fluids, which have a very small viscosity. As a mathematical method, we have a second order partial differential equation that the diffusion coefficient is much smaller than the magnitude of the convection coefficient. These are a type of boundary layer problems which instabilities will arise in their numerical solution. In this talk, a brief discussion about the properties of these problem is presented. Also some existing ideas are reviewed for solving these problems numerically. Finally, the Galerkin boundary node method is analyzed for magneto-hydrodynamic (MHD) equation.

Amir abbass Varshovi
Institute for Research in Fundamental Sciences
December 18, 2014 (27th Azar 1393) at 11:00-12:00

Abstract: I will start with a brief review on quantization theory including the ideas of deformation quantization of Poiison manifolds and Weak quantization approach reviewing the related theorems of Weyl, Wigner, Egorov, Groenewold, Lichnerowitz, Fedosov, Kontsevich, etc. Then using the theory of alpha^*- cohomology (defined by myself) as a modified version of alpha-cohomology (introduced partly by Lizzi et all.) I will classify all the quantum behaviors of translation-invariant non-commutative quantum field theories. A junction to the Kontsevich's theorem will be worked out which leads to classification of translation-invariant structures of space-time. I also apply this achivements to generalize the Drinfeld's twisted Poincare symmetry of translation-invariant non-commutative quantum field theories.

Mahmoud Filali
University of Oulu,Finland
November 30, 2014 (9th Azar 1393)

Abstract: We devise a fairly general method for estimating the size of quotients between algebras of functions on a locally compact group. This method is based on the concept of interpolation set we introduced and studied recently and unifies the approaches followed by many authors to obtain particular cases. Joint work with Jorge Galindo

You can download the Photos here

Mohammad Reza Salarian
Kharazmi University
November 6, 2014 (15th Aban 1393) at 11:00-12:00

Abstract: Recently many of the finite simple groups have been characterized by their 3-local information. One of the main ideas behind these characterizations is a recent program led by Meierfrankenfeld, Stellmacher and Stroth to understand the structures of so called groups of local characteristic p, p is a prime number. In this talk we will give a short report about these characterizations.

       مقداد قاری
پژوهشگاه دانشهای بنيادی
یکم آیان ماه 1392 ساعت 14:00 

چكيده : در منطق ریاضی سیستمهای مختلفی برای اثبات وجود دارد، که مهمترین آنها عبارتند از سیستمهای اصل موضوعی، استنتاج طبیعی، حساب رشته ای، و روش تابلوها. در بین این سیستمهای اثبات روش تابلوها برای ایجاد اثباتهای خودکار و ماشینی و برای پیاده سازی در کامپیوتر بیشتر مورد توجه قرار گرفته است. اثباتها در روش تابلویی به صورت درخت میباشند. برای اثبات یک فرمول در روش تابلوها ابتدا فرض میکنیم که آن فرمول نادرست است، سپس قواعد موجود در سیستم را روی آن فرمول به کار میبریم. در نهایت اگر به تناقض رسیدیم آن فرمول اثبات میشود، و اگر به تناقض نرسیدیم آن فرمول نادرست است و میتوان با استفاده از درخت موجود یک مدل نقض برای آن ساخت.  در این سخنرانی سیستمهای اثبات تابلویی برای منطقهای توجیه معرفی میشوند، و سپس با استفاده از آنها الگوریتمی برای اثبات فرمولها ارایه میشود.

Quantum parameter estimation with imperfect reference frames  (Photos)

Mehdi Ahmadi
University of Nottingham, England
October 2, 2014 (10th Mehr 1393) at 11:00-12:00

Abstract: Quantum metrology studies quantum strategies which enable us to outperform their classical counterparts. In this framework, the existence of perfect classical reference frames is usually assumed. However, such ideal reference frames might not always be available. The reference frames required in metrology strategies can either degrade or become misaligned during the estimation process. We investigate how the imperfectness of reference frames can lead to both correlated and uncorrelated noise which then can affect the ultimate precision limits in measurement of physical parameters. Moreover, since quantum parameter estimation can be phrased as a quantum communication protocol between two parties, our results provide deeper insight into quantum communication protocols with misaligned reference frames. Our framework allows the study of general noise on the efficiency of such schemes.

Positive Cones of *-Algebras  (Photos)

Golam Hosein Esslamzadeh
Shiraz University
September 11, 2014 (20th Shahrivar 1393) at 11:00-12:00

Abstract: Operator algebras are equipped with rich algebraic, geometric and topological structures such that one naturally asks which of these structures have made a particular theorem work. Positivity is among the main tools in the study of operator algebras. In this talk first we review quickly some classical results on the interplay between positivity and the structure of C*-algebras. Then, we present some successful generalizations to Banach *-algebras and arbitrary *-algebras. This confirms the fundamental role of algebraic structure in the aformentioned classical results.

Maximum Entropy and Maximum Dynamic Entropy models

Majid Asadi
University of Isfahan and IPM
June 19, 2014 (29th Khordad 1393) at 11:00-12:00

Abstract: The maximum entropy (ME) approach is an extension of Laplaces principle of insufficient reason to produce a model for the data-generating distribution based on partial knowledge.In ME approach, partial knowledge about the data-generating distribution is formulated in terms of some information constraints and the model is obtained by maximizing the Shannon entropy under these constraints. In this talk, after defining the concept of Shannon entropy,we will describe the ME principle and show how it provides a natural conceptual role for many standard probability distributions. Then we give the concept of dynamic Shannon entropy which leads to information measures that depend on time. We introduce the concept of maximum dynamic entropy (MDE) model, where formulation of constraints for the MDE model is in terms of the evolution paths of the hazard function and mean residual lifetime function.

Introduction to Ramsey Theory 

Gholamreza Omidi
Isfahan University of Technology and IPM
May 8, 2014 (18th Ordibehesht 1393) at 11:00-12:00

Abstract: The basic paradigm of Ramsey theory is that if a sufficiently large structure is partitioned arbitrarily into finitely many parts, at least one part has a particular property, and thus total disorder is impossible. We will illustrate this principle by means of a number of results from graph theory, number theory,and combinatorial geometry.

Ahmad Parsian
University of Tehran
April 24, 2014 (4th Ordibehesht 1393) at 11:00-12:00

Abstract: In this talk, briefly we introduce the framework of Bayesian Statisticians and introduce different types of Bayesians. Then we focus on the prior choice and explain the concept of non-informative priors through a simple example. We are going to construct a simple argument and illustrate why the flat priors are not necessarily the most non-informative. We end the talk with lessons of this discussion and final remarks.

Alex Martsinkovsky
Northeastern University
April 10, 2014 (21st Farvardin 1393) at 11:00-12:00

Abstract: This is joint work with A. Vlassov. We will show how the connection between bialgebras and monoidal structures can help decompose the tensor product of representations. The talk will be elementary and accessible to undergraduate math students who have had a first course in linear algebra. All concepts, including that of the tensor product, will be defined and explained, and the main idea will be illustrated by decomposing products of Jordan blocks.

Morteza Esmaeili
Isfahan University of Technology and IPM
February 6, 2014 (17th Bahman 1392) at 11:00-12:00

Abstract: Finding reliable and efficient methods for the storage and transmission of data over noisy communication channels is a challenging problem. Related to this, some of the graph theory concepts and some special types of graphs have been efficiently exploited. Given a source X with information H(X), tree-graphs are used for representation and source-encoding of X. Two types of graphs, known as Tanner graph and trellis diagram, have provided considerable contribution to communication engineering. Given a system of linear equations S, the system can be represented by a bipartite graph known as Tanner graph, and any subspace C of the n-dimensional vector space F_q ^n over F_q can be represented by a trellis diagram. A given linear code C, can be represented by each of these two types of graphs. There are methods for constructing structured regular low-density parity-check (LDPC) codes (codes with sparse Tanner graphs) based on combinatorial designs. Construction of structured regular quasi-cyclic (QC) LDPC codes based on Steiner systems and difference sets is considered. Steiner systems with t ≥ 3 are used to generate girth-6 LDPC codes. Given a Steiner system (X ), this system and its residual design with respect to an arbitrary point x in X are employed for code construction. Also, difference sets are used to give a method for constructing structured regular QC-LDPC codes. Let F_q be a field with q elements and assume that D = {d_1, ..., d_k} is a (v, k, 1)-difference set for Z_v with d_1 < d_2 < ... < d_k. Depending on v = q - 1, v ≥ 2d_k or v ≥ 2d_{k-1}, three code construction methods are given that produce regular 4-cycle free codes.
 

(Photos)  همگرايی فيزيک نظری و زيست شناسی در مقياس نانو

دکتر هاشم رفيعی تبار
پژوهشکده علوم نانو، پژوهشگاه دانشهای بنيادی
دهم بهمن ماه 1392 ساعت 11:00 الی 12:00

چكيده : قرن حاضر، دوران متحد ساختن علوم فيزيکی و علوم زيستی است ، که منجر به پيدايش علوم و فناوری همگرا خواهد شد. اين همگرائی  دو حوزه بزرگ علوم زيستی و علوم فيزيکی در مقياسهای اتمی و ملکولی محقق خواهد شد،  زيرا در اين مقياسها است که اجزای بنيادی ماده فيزيکی،  ماده حيات دار و ماده هوشمند، يعنی نانو ساختارهای فيزيکی و زيستی، شکل گرفته و سازمان مي يابند. دانش ما در حوزه های علوم زيستی و غير زيستی نشان ميدهد که از ترکيب ساختن ارگانيک  و متعامل اين نانو ساختارها  ساختار های بزرگتر فيزيکی و زيستی ، مانند بافتها و ارگانيسمهای زيستی بسيار پيچيده ، بدست ميايد.  اين همگرائی بدون شک  در طی پنجاه سال آينده انجام خواهد پذيرفت، زيرا مطابق پژوهشهای بسيار پيشرفته موجود، ساختار و عملکرد سامانه های زيستی و غير زيستی تحت هدايت اصول واحد و عملکرد قوانين واحد قرار دارند. آنچه که ساختارهای زيستی و غير زيستی را از هم متمايز ميسازد، نه حضور قوانين فيزيکی مختلف، بلکه ساز وکارهای مختلفی است که اين قوانين از طريق آنها خود را در اين دو حيطه نشان ميدهند. نهايتا بايد بتوان پديده های زيستی مانند حيات و هوشمندی سامانه های زيستی را از نظم سازمانی ماده فيزيکی تشکيل دهنده آنها، که مطابق قوانين نظريه کوانتومی فعاليت ميکنند، بدست آورد.  اين خط پژوهشی  متکی بر بينشی است که خواص ارگانيسمهای زيستی را به ساختار فيزيکی آنها مرتبط ميسازد. اکنون با وجود امکانات گسترده محاسباتی و انجام مدل سازی های دقيق و پيشرفته رايانه ای ميتوان برای اولين بار در تاريخ علم رابطه عميق مابين ساختار و عملکرد را عددی کرده و بطور کمی محاسبه نمود. در اين نوشته هدف  ما از يک سو معرفی مفاهيم نظری مربوط به همگرائی علوم زيستی وعلوم فيزيکی است و از سوی ديگرارائه اين پيشنهاد نظری است که بهترين نقطه تلاقی اين دو حوزه در مقيا س نانو قرار دارد، و اين  تلاقی خودمنجر به پيدايش حوزه کاملا جديدی در صحنه دانش بنام علم زيست-نانو شده است. بخشی از اين سخنرانی مربوط به بررسی يکی از مصاديق اين  همگرائی است. در اين رابطه، فيزيک نانو روباتهای زيستی بطور اجمال معرفی شده و نشان داده خواهد شد که چگونه ميتوان با استفاده از مکانيک استوکاستيک موجود، ديناميک اين ارگانيسم های بسيار زيبا را دقيقا مدل کرد.

Mahmmad Reza Koushesh
Isfahan University of Technology and IPM
January 23, 2014 (3rd Bahman 1392) at 11:00-12:00

Abstract: A (topological) space Y is called an extension of a space X if Y contains X as a dense subspace. An extension Y of X is called a one-point extension if Y-X is a singleton. Compact extensions are called compactifications and connected extensions are called connectifications. It is well known that every locally compact non-compact space has a one-point compactification (also known as the Alexandroff compactification) obtained by adding a point at infinity. A locally connected disconnected space, however, may have no one-point connectification. There is an old question of Alexandroff of characterizing spaces which have a one-point connectification. Motivated by this, we prove that in the class of completely regular spaces, a locally connected space has a one-point connectification if and only if it contains no compact component.
 

Mahmood Behboodi
Isfahan University of Technology and IPM
January 9, 2014 (19th Day 1392) at 11:00-12:00

Abstract: This talk presents an extensive account of results, obtained by several authors over the past 80 years, on rings R characterized by the property that a subcategory of the category of R-modules whose objects are direct sum of cyclic modules. First we give a brief discussion on rings over which each module is a direct sum of cyclic modules. Then we present the structure of commutative rings over which each finitely generated module is a direct sum of cyclic modules (called FGC-rings). Also, we consider commutative rings for which every ideal (or, every prime ideal) is a direct sum of cyclic modules and then we describe the ideal structure of such local rings. The connections of this theory with many important challenging problems in related areas are discussed. First, we give structure and isomorphism theorems for finite rings and state our main result to classify (up to isomorphism) the finite rings of a given order. Also, based on these results, we describe an algorithm to calculate the structure of all such rings. We have implemented our new algorithm in Maple, and apply it to an example. Finally, we derive the existence results for solutions of system of linear congruence equations over a principal ideal domain, or more generally, over a commutative FGC-ring.

 (Photos) کتاب عالم را با عينک کهکشان ها بخوانيم 

دکتر حبيب قرارخسروشاهی
پژوهشکده نجوم، پژوهشگاه دانشهای بنيادی
پنجم دی ماه 1392 ساعت 11:00 الی 12:00

چكيده
كهكشانها پيش از آن كه بلوك هاي تشكيل دهنده عالم خطاب شوند، سحابي های كم سو در آسمان شب هاي تاريك قرن  ١٩  بودند. ديري نپاييد كه مشاهدات كهكشانها پنجره ای به انبساط عالم گشود، که شايد بتوان از آن به عنوان مهم ترين مشاهده رصدی در قرن بيستم  در شناخت كيهان ياد کرد. امروز دسته ای از كهكشانها بزرگترين مراكز تجمع باريون در آسمان قابل رويت، بزرگترين أجرام ستاره اي و ميزبان پرانرژي ترين پديده ها بعد از مهبانگ هستند درحالي كه برخي ديگر از آنها آرام ترين، نرم ترين و بي رويدادترين اجرام هستند. كهكشانها هم به تنهايي و هم به صورت گروهي جالبند. به دليل نزديكي مقياس زماني تشكيل و تحول كهكشانها و عمر عالم  كهكشانها  كليد برخی اسرار تشكيل  عالم  را در اختيار دارند. بزرگي و جرم كهكشانها درست به اندازه ای است  كه  بتواند وجود ماده  تاريك را به چالش بکشد. در اين فرصت آخرين ياقته هاي مطالعات کهکشانها و سيستم های کهکشانی بر اساس رصدها و مدل سازی ها از غول تا کوتوله، غنی و فقير، فشرده و پخش شده، پير تا نوزاد، با موتور روشن و خاموش ارائه می شود.

Abstract: Before galaxies being dubbed as the building blocks of the Universe, they were identified as nebulae, diffuse extended objects in dark sky of 19th century. Soon their observations opened the window to the expanding Universe, perhaps the single most important observation for our understanding of the cosmos. Today, some category of galaxies are the largest concentration of baryons in the visible sky, largest stellar objects, hosts to most energetic phenomenon in the universe after the Big Bang, while some are the most quiet, smooth and event less entities. They are interesting on their own and also as a group. The time scale in which galaxies form and evolve closely follows the life time of the Universe thus they hold the key to some of its mysteries. Their scale and mass is just right amount to challenge dark matter presence. I will report on the latest development in our studies of galaxies and galaxy systems which are based on observations and modelings from giants to dwarfs, rich to poor, loose to compacts, old to newborn, with out without running engines!

  (Slide Show, Photos)  پژوهش در دوره نقل علم

دکتر رضا منصوری
دانشگاه صنعتی شريف
چهاردهم آذر 1392 ساعت 11:15 الی 12:05

چكيده
کشور ما ايران به لحاظ توسعه در يک دوران گذار است. در اين دوران گذار مفهوم علم و به تبع آن پژوهش، با در نظر گرفتن تحولات تاريخی کشورمان، در شرف تحول است. در اين يکصد سال تاسيس نهادهای مدرن علمی در ايران به زحمت فرصتی  پيدا  شده  که  ما در خصوص تحول  معنايی اين مفهوم پيچيده مدرن  تامل  کنيم. واقعيت اين است که در بهترين حالت مشغول نقل دانشی هستيم که  آفرينندگان آن در بخش ديگری از جهان ساکن اند، و ما در اين دوران  نقل دچار سندرم دوره نقل شده ايم، بدون اين  که  در سياست گذاري ها  و برنامه های اجراِيی به  ويژگی های اين دوران توجه  کنيم.  توجه  به اين سندرم موفقيت های ما را در توسعه علمی سريع تر و موثر تر می کند.

Abstract: When G is a locally compact Hausdorff topological group and H is a closed subgroup of G, the quotient space G/H, equipped with the quotient topology, is a locally compact Hausdorff space that G acts on it from the left. Although, G/H is a topological group just when H is a normal subgroup of G and when H is not normal, we cannot define a binary operation and an inverse function on G/H by using the operators on G, in a natural way, one may find some structural transition between the function spaces on G/H and the function spaces on G. On these spaces, there exist always Radon measures whose translations are absolutely continuous with respect to themselves, namely strongly quasi-invariant measures. One may consider the function spaces of measurable functions on G/H, with respect to such a measure, and investigate their structures and relations between them. We aim to consider these kind of spaces, which contains a large amount of locally compact Hausdorff spaces, and investigate some properties of their function spaces.

Abstract: I will be discussing the concept of naturalness in other fields including in mathematics and then restrict to High energy Physics. Then I will discuss the urgency of the relevant developments in theoretical physics in relation naturalness in view of the recent discovery of the Higgs particle at LHC, where IPM scientists have also been involved.

On Products of Conjugacy Classes and Irreducible Characters in Finite Groups (Slide Show, Photos)

Mohammad Reza Darafsheh
University of Tehran
June 27, 2013 (6th Tir 1392) at 11:00-12:00

Abstract: Let G be a finite group. For irreducible complex characters χ and Φ of G the irreducible constituents of χΦ is denoted by η(χΦ). If A and B are two conjugacy classes in G, then AB is a union of conjugacy classes in G and η(AB) denotes the number of distinct conjugacy classes of G contained in AB. In this paper we investigate the current research on the impact of their η-functions on the structure of G as well as some similarity between them.

Dirichlet-to-Neumann Semigroup Acts as a Magnifying Glass (Slide Show, Photos)

Hassan Emamirad
School of Mathematics, IPM
June 20, 2013 (30th Khordad 1392) at 11:00-12:00

Abstract: This talk is divided in two parts; visibility and invisibility related to the Dirichlet-to-Neumann operators.First we define this operator and the related semigroup. We show that in the case represented by P.Lax this semigroup acts as a magnifying glass. We illustrate this magnification through a movie and we explain the numerical methods for implementation of this movie. The second part is concerned on invisibility. This is a highly attractive subject in Riemannian geometry and applied mathematics described as cloaking. This subject was performed afterward of Luc Tartar’s counter-example in Calderón’s inverse problem of nonuniqueness of conductivity in anisotropic case. He showed that one can construct two different conductivities which have the same correspondent Dirichlet-to-Neumann operator. This gives as a result in nanotechnology, the construction of metamaterial, which is a sort of fabric which can cloak the objects.

Signaling Theory, Image-based Incentives (Slide Show, Photos)

Ali Maziki
Institute for Management and Planning Studies (IMPS)
June 13, 2013 (23th Khordad 1392) at 11:00-12:00

Abstract: We use a signaling model of social behavior based on Benabou and Tirole (2011) to explore the optimal level of traditional economic incentives (rewards, fines) relative to image-based incentives (awards, shaming penalties). We derive social multipliers that determine the impact of both policies on the aggregate level of pro-social behavior. We show that the optimal mix includes both policy instruments, and that high levels of image-based incentives are associated with `extreme' levels of pro-social behavior, i.e. situations where very few or very many people act pro-socially.

Minimalist's Electromagnetism (Slide Show, Photos)

Yousof Sobouti
Institute for Advanced Studies in Basic Sciences (IASBS)
May 30, 2013 (9th Khordad1392) at 11:00-12:00

Abstract: That the universal constancy of the speed of light is a logical consequence of Maxwell's equations is common knowledge. Here we show that the converse is also true. That is, electromagnetism (EM) and electrodynamics (ED) in all their details can be derived from the simple assumption that the speed of light is a universal constant and the common observation that there are the so-called charged particles that act on each other. The consequences reach far. Conventional EM and ED are observation based. The proposed alternative spares all observational foundations of EM, only to reintroduce them as theoretically derived and empiricism-free laws of Nature. There are merits to simplicity. For instance, if ∇.B = 0 emerges as a corollary of the formalism, then nonexistence of magnetic monopoles will be a proven theorem and a reality. Similarly, if Poisson's equation is derived from some first principles, then the inverse square law of Coulomb force becomes an exact law as long as the accepted first principles are tenable.

Geometry of Totally Disconnected Metric Spaces (Photos)

Massoud Amini
Tarbiat Modares University and IPM
May 23, 2013 (2th Khordad1392) at 11:00-12:00

Abstract: Approximately finite dimensional $C^*$-algebras (AF-algebras) are direct limits of finite dimensional $C^*$-algebras (finite direct sums of full matrix algebras) and could be seen as the norm closure of increasing union of such algebras. There is a canonical way to associate a Dirac operator to such an increasing sequence and give the metric on the state space. There is no upper bound to the growth of eigenvalues of the Dirac operator in this case, and in a sense, the lack of such an upper bound, forces the Dirac operator to be acting on an AF-algebra. As a concrete example, the $C^*$-algebra of continuous functions on the Cantor set is an AF-algebra, where the latter carries the topological data of the set. Following the general philosophy of Non Commutative Geometry (NCG), It is proposed that the geometric data is not only encoded in the spectral triple of the C*-algebra of continuous functions on the set (as Alain Connes has already shown) but also in the filtration of that algebra as an increasing union of sums of matrix algebras. We give a report on the recent work of Erik Christensen and Cristina Ivan on the spectral triples for AF-algebras (Jour. Oper. Theory 56:1 (2006), 17-46) and its application in encoding the geometric data of certain totally disconnected metric spaces.

Cohen-Macaulay Representation Theory and n-representation-finiteness

Osamu Iyama
Nagoya University, Japan
May 9, 2013 (19th Ordibehesht 1392) at 11:00-12:00

Abstract: Representation-finiteness of Noetherian algebras is a classical subject in representation theory studied by many authors including Auslander, Drozd, Roggenkamp, Hijikata, Reiten, Van den Bergh, Herzog, Knoerrer, Buchweitz, Greuel and Schreyer. In this lecture we discuss higher dimensional Auslander-Reiten theory for Noetherian algebras. We give a systematic construction of n-representation-finite Noetherian rings. Then we generalize Auslander's algebraic McKay correspondence by showing that their stable categories of Cohen-Macaulay modules are triangle equivalent to cluster categories which appear in categorification of Fomin-Zelevinsky cluster algebras.
 

Geometry and Topology in Dimensions 3 and 4 (Photos)

Eaman Eftekhary
School of Mathematics of IPM
April 25, 2013 (5th Ordibehesht 1392) at 11:00-12:00

Abstract: We will review some parts of the development in low dimensional topology and geometry in the past 50 years or so. Things that make dimensions 3 and 4 harder than higher dimensions, the resolution of the (topological) Poincare conjecture, and the methods developed for the detection of exotic smooth structures in dimension 4 will be discussed in the talk.

The Max-Planck Institute is MPI not IPM (Photos)

Siamak Yassemi
School of Mathematics of IPM and University of Tehran
April 11, 2013 (22th Farvardin 1392) at 11:00-12:00

Abstract: The Max-Planck Institute for Mathematics was founded in 1981 in Bonn-Germany and has become a major international center for mathematics research.Without any doubt, the MPI in Bonn retains its role as the top research institute for pure mathematics in Germany. Much of the credit for the success of the MPI goes to its founding director, Friedrich Hirzebruch, who has made enormous contributions to rebuilding Mathematics research in Germany after World War II. Since MPI was always one of the good sample for IPM to follow its activity, I will give a history of founding MPI and its status at this time.

           درباره معرفت رياضي  (Photos)  

حميد وحيد
پژوهشكده فلسفه تحليلي، پژوهشگاه دانشهاي بنيادي
دهم اسفند ماه 1391 ساعت 14:30 الي 15:30

چكيده:
فلسفه ریاضی از دو پرسش اساسی تشکیل می شود: (1) ریاضیات دربارۀ چیست؟ و (2) علم به حقایق ریاضی چگونه ممکن است؟ پاسخ به این دو پرسش نمی تواند مستقل از یکدیگر باشد.در این سخنرانی پس از توضیح رویکردهای متفاوت به معرفت ریاضی، مؤلفه های گوناگون آن مورد بررسی قرار خواهند گرفت.

The Quantum Double Model as a Topologically Ordered Phase (Slide Show, Photos)

Salman Beigi
School of Mathematics of IPM
February 28, 2013 at 11:00-12:00

Abstract: A phase of matter is called topologically ordered if it cannot be characterized by its local properties. Quasi-particle excitations of a topologically ordered phase are described by a braided tensor category, for which the category of representations of a quasi-triangular Hopf algebra provides a typical example. Kitaev in 1997 gave the first example of a model whose ground space is topologically ordered and whose quasi-particle excitations are in one to one correspondence with irreducible representations of the quantum (Drinfeld) double of a finite group. In this talk after a brief review of the meaning of topological order and its relation to tensor category theory, the Kitaev model corresponding to a finite group is described. We first start with the smallest group Z_2, and then generalize everything to arbitrary groups. Then we discuss that boundaries of the Kitaev model are characterized by certain algebras in the corresponding tensor category, and that using these boundaries, domain walls and phase transitions can be studied. Finally based on this rich mathematical structure some non-trivial symmetries in the Kitaev model will be presented.

Classification  of  Rough  Surfaces Using Schramm-Loewner Evolution (Photos)

Shahin Rouhani
Sharif University of Technology and IPM
February 21, 2013 at 11:00-12:00

Abstract: Theory of Schramm-Loewner Evolution (SLEk) has been developed originally as theory of random simple curves with conformally invariant probability distribution, describing domain interfaces at criticality, for two dimensional statistical mechanics models. I argue that Iso-height lines on rough surfaces (deposited or computer generated) can also be regarded as SLEk . This may be regarded as evidence of conformal invariance in systems far from equilibrium. Perhaps this connection leads to a classification of self affine surfaces in 2+1 dimensions. In this talk we review SLE Curves in Turbulence, KPZ surface, Ballistic Deposition model (BD), and a few more models. Finally discuss watersheds and optimal paths through random media.

Various Perspectives for IPM-Isfahan Branch

Javad Asadollahi
School of Mathematics of IPM and University of Isfahan
February 14, 2013 (26th Bahman 1391) at 14:00-15:00

Abstract: One of the most important factors for the success of a research institute is the reasonable vision that should be considered for its future. There are various visions one may anticipate for a new founded research institute like IPM-Isfahan. In this meeting we will discuss some of these visions for 30 minutes. The next 30 minutes will be devoted to the comments and hints by the audiences.

Gene Network; A Bayesian Multivariate Analysis (Photos)

Hamid Pezeshk
University of Tehran
February 7, 2013 at 11:00-12:00

Abstract: There are several methods for inference about gene networks, but there are few cases in which the historical information has been considered. In this research we deal with inference on a gene regulatory network.We apply a Bayesian framework to use the available information. Assuming a proper prior distribution and taking the dependency of parameters into account, we seek a model to obtain a reliable model. We also deal with the estimation of hyper parameters. Two methods are considered. Their results will be compared by the use of a simulation based on Gibbs samplers. The strengths and weaknesses of each method are briefly discussed.

Symmetries and Physics (Photos)

Mohammad Mehdi Sheikh-Jabbari
School of Physics, IPM
January 24, 2013 at 11:00-12:00

Abstract: Dynamics of physical systems is generally driven either by energetics or the entropy, toward states or configurations which minimize energy (Hamiltonian) or maximize the entropy. However, the states in the phase or configuration spaces are not distinguished merely by their energy or entropy. Such states are related by symmetries. In the language of Lagrangian or Hamiltonian dynamics or field theory, symmetries are hence defined as transformations on the phase space or on the spacetime over which the theory is defined, which keep the action invariant. This definition provides an extension of the definition given earlier. Using this definition one can classify the symmetries depending on the transformations. The other concept which has appeared very fruitful in all branches of physics is the notion of ``approximate symmetry'' and the ``(spontaneous) symmetry breaking''. In this talk I will review the classification of symmetries, their implications and their breaking by considering examples from high energy physics, cosmology and condensed matter physics.

Brain and Cognition

Hossein Esteky
School of Cognitive Sciences, IPM
January 10, 2013

Abstract: In this talk I will briefly explain the evolution of primate brain leading to current human species cognitive capabilities. I will then present evidence from my research showing how visual cognition is emerged in primate brain. I will particularly emphasize on our discovery that electrical stimulation of face neurons causes face perception even in the absence of visual stimulus.

Information Measure of Dependence: Some Virtues and a Caveat (Slide Show)

Ehsan Soofi  
University of Wisconsin-Milwaukee, USA
December 27, 2012 at 14:00-15:00

Eigenvalues of Graphs (Slide Show)

Behruz Tayfeh-Rezaie
School of Mathematics, IPM
December 27, 2012

What Is the Mathematical Physics (Slide Show)

Rasool Roknizade
University of Isfahan, Isfahan
November 22, 2012

Deformation of Analytic and Algebraic Structures

Alice Fialowski
Eötvös Loránd University, Hungary
October 24, 2012

Evaluation of Journals (Slide Show)

Alireza Abdollahi
University of Isfahan, Isfahan
October 18, 2012

How the IPM Evaluates the Research Groups

Saeid Azam
University of Isfahan, Isfahan
October 11, 2012