# Lectures, seminars and dissertations

* Dates within the next 7 days are marked by a star.

Pekka Lehtelä

**On the regularity of supersolutions to the porous medium equation**

*** Today * ** Friday 28 April 2017, 14:15, M3 (M234)

Harmonic analysis and PDE seminar

Prof. David Rios Insua (ICMAT-CSIC and Royal Academy of Sciences, Spain)

**Adversarial Risk Analysis: Concepts, Applications and Challenges**

*** ** Tuesday 02 May 2017, 15:15, M1 (M232)

Our focus will be on problems in which two or more agents confront (as in non-cooperative game theory) and the consequences that they receive are random (as in risk analysis) and depend on the actions of all participants (as in game theory). This is motivated by problems in relation with high-profile terrorist attacks, business decision making and cyber-security.
Most authors in this context would use game theoretical methods based on variants of Nash equilibria concepts. However, this is not always satisfactory in most of the above applications since beliefs and preferences of adversaries will not be readily available, frequently violating game theoretic common knowledge assumptions. In contrast, we focus on Adversarial Risk Analysis (ARA), an emergent paradigm for the type of problems we consider. ARA provides one-sided prescriptive support to a DM, maximizing her subjective expected utility, treating the adversaries' decisions as random variables. ARA models the adversaries' decision-making problems and, under assumptions about their rationality, tries to assess their beliefs and preferences. Then, ARA can predict their optimal actions. However, the uncertainty about the adversaries' judgements is propagated into their decisions, leading to random optimal adversarial decisions which provide the necessary distributions over the adversaries' decision. The main goals of ARA are to weaken standard common knowledge assumptions and provide more flexible models for opponent behavior. ARA is explicitly Bayesian in that subjective distributions are employed to express the uncertainties of the analyst.
We shall outline basic concepts in ARA, some relevant applications and identify a few challenges.

Colloquium of Mathematics and Systems Analysis

Prof. Bharath Sethuraman (California State University, Northridge)

**TBA**

Tuesday 09 May 2017, 15:15, M3 (M234)

ANTA Seminar: Algebra, Number Theory, and Applications to Communications and Computing / Karpuk, Kaski, Hollanti, Greferath

Thomas Westerbäck

**Combinatorial coding theory via polymatroids**

Wednesday 10 May 2017, 15:15, M3 (M234)

Matroid theory can be used to analyze many interesting properties of linear codes over finite fields. Recent research has proven matroid theory to be a valuable tool in several areas in coding theory, e.g. in distributed storage, index coding and network coding. Polymatroids, a generalization of matroids, can be associated with any finite code. In this talk I will present how polymatroids and codes are closely related via entropy and how polymatroid theory can be used in order to analyze many interesting properties of codes. New coding theoretical results will be given in the setting of polymatroids. These results can therefore also be applied to non-code objects that are associated with polymatroids.

ANTA Seminar: Algebra, Number Theory, and Applications to Communications and Computing / Karpuk, Kaski, Hollanti, Greferath

Dissertation

Amaro Barreal

**Doctoral thesis defense: Lattice codes for physical layer communications**

Thursday 11 May 2017, 14:00, M1 (M232)

Opponent: Prof. Bharath Sethuraman

ANTA Seminar: Algebra, Number Theory, and Applications to Communications and Computing / Karpuk, Kaski, Hollanti, Greferath

Christopher Hopper

**TBA**

Friday 12 May 2017, 14:15, M3 (M234)

Harmonic analysis and PDE seminar

Prof. Daina Taimina (Cornell University)

** Study mathematics and ... become an artist?**

Tuesday 16 May 2017, 15:00, C-hall (Y205)

When I was in middle school I was a good student and had very good grades in all subjects...except in art class where I was struggling to draw the way my teacher thought was the right way. I accepted my teacher's judgement that I can do anything but art and went to study mathematics. Could I imagine that some fifty years later I will be known as an artist? Mathematics and art are not too distant. In my talk, I will discuss the interplay between mathematics and art from my own perspective.

Joint Mathematics and Arts and Women in Mathematics Colloquium / Kirsi Peltonen

Dimitrios Ntalampekos (UCLA)

**TBA**

Friday 19 May 2017, 14:15, M3 (M234)

Harmonic analysis and PDE seminar

Smiljana Jaksic (University of Belgrade, Serbia)

**Spaces of ultradistributions with applications to pseudo-differential operators**

Wednesday 24 May 2017, 12:15, M3 (M234)

This talk is based on joint works with Stevan Pilipovic and Bojan Prangoski.
The first part of the talk is devoted to spaces of test functions and ultradistributions on the positive orthant of the Euclidean space,
which can be described as analogous to the Gelfand-Shilov spaces and their dual spaces.
Such ultradistributions are characterized through the Laguerre expansions.
Furthermore, the full topological description of the spaces is given.
The second part is devoted to the class of the Weyl pseudo-differential operators
with radial symbols from the ultradistribution spaces.
The continuity properties of these classes of pseudo-differential operators
over the Gelfand-Shilov spaces and their dual spaces are proved.
In this way, the classes of the Weyl pseudo-differential operators are extended
to those with the radial symbols with the exponential and sub-exponential growth rate.

Seminar on analysis and geometry

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