Oregon

Mon 15 Oct 2018, 4:00pm
Algebraic Geometry Seminar
Math 126

Exoflops

Math 126
Mon 15 Oct 2018, 4:00pm5:00pm
Abstract
The derived category of a hypersurface is equivalent to the
category of matrix factorizations of a certain function on the total space
of a line bundle over the ambient space. The hypersurface is smooth if
and only if the critical locus of the function is compact. I will present
a construction through which a resolution of singularities of the
hypersurface corresponds to a compactification of the critical locus of
the function, which can be very interesting in examples. This is joint
work with Paul Aspinwall and Ed Segal.
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UBC

Tue 16 Oct 2018, 4:00pm
Discrete Math Seminar
ESB 4127

(0,1,2)matrices can sometimes behave like (0,1)matrices

ESB 4127
Tue 16 Oct 2018, 4:00pm5:00pm
Abstract
This is joint work with Jeffrey Dawson, Linyuan Lu and Attila Sali.
We define simple matrices as those whose entries are chosen from {0,1,2} and for which no columns are repeated. We consider the extremal problem of how many columns can an mrowed simple matrix A have, subject to the condition that A avoids certain submatrices.
We consider some forbidden submatrices (configurations) that seem to force A to behave like a (0,1)matrix. Define T_k(a,b,c) to be the kxk matrix with b's on the diagonal, a's below the diagonal and c's above the diagonal. These generalize the identity and triangular matrices. There are such 8 matrices to forbid which seem to force A to behave like a (0,1)matrix. Some preliminary results are given.
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Universidad Nacional de Colombia sede Medellín

Wed 17 Oct 2018, 2:50pm
Topology and related seminars
ESB 4133 (PIMS Lounge)

Transitionally commutative bundles

ESB 4133 (PIMS Lounge)
Wed 17 Oct 2018, 2:50pm3:50pm
Abstract
The main goal of this talk is to introduce transitionally commutative principal Gbundles and to show that they can be classified homotopically using a space B_comG that is called the classifying space for commutativity in G. In the second half of the talk I provide some examples of bundles that are trivial as principal Gbundles but not as transitionally commutative bundles.
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Dept of Evolutionary Studies of Biosystems, The Graduate University for Advanced Studies (SOKENDAI), Japan

Wed 17 Oct 2018, 3:00pm
Mathematical Biology Seminar
ESB 4127

Allele frequency spectrum in a cancer cell population

ESB 4127
Wed 17 Oct 2018, 3:00pm3:45pm
Abstract
A traditional populationgenetics approach studies geneaologies in a population of a fixed size, which forms the basis of several spectral theories of finite samples. In contrast, a population of tumor cells typically experiences an exponential growth phase in its initial progression, which is far from constant population size. In this work, I develop two different numerical procedures, one of which is based on forwardintime and the other is based on backwardintime treatment, to derive allele frequency spectrum in such exponentially growing cancer cell populations. We find significance bias toward singletons both analytically and numerically, which reflects the fact that most observed mutations have recent origins in a growing population.
This work was done in collaboration with Prof. Hideki Innan 

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University of British Columbia

Wed 17 Oct 2018, 4:00pm
Probability Seminar
ESB 2012

The DobrushinLanfordRuelle theorem on steroids

ESB 2012
Wed 17 Oct 2018, 4:00pm5:00pm
Abstract
The DobrushinLanfordRuelle theorem gives sufficient
conditions on sets of configurations on the ddimensional lattice so
that (1) every measure which maximizes the topological pressure is a
Gibbs measure and (2) every Gibbs measure maximizes the topological
pressure. In this talk we shall discuss a generalization of this theorem
in several directions: the lattice is now an arbitrary countable
amenable group, we permit the existence of a random environment and
consider measures that project onto it, and we relax the required
conditions of (1) to a much larger class of dynamical systems. We shall
also present a few applications of this theorem.
This is joint work with Ricardo GómezAíza, Brian Marcus and Siamak Taati.
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University of Toronto

Fri 19 Oct 2018, 4:00pm
Department Colloquium
ESB 2012

CRMFieldsPIMS prize lecture: The KPZ fixed point

ESB 2012
Fri 19 Oct 2018, 4:00pm5:00pm
Abstract
The (1d) KPZ universality class contains random growth models, directed random polymers, stochastic HamiltonJacobi equations (e.g. the eponymous KardarParisiZhang equation). It is characterized by unusual scale of fluctuations, some of which appeared earlier in random matrix theory, and which depend on the initial data. The explanation is that on large scales everything approaches a special scaling invariant Markov process, the KPZ fixed point. It is obtained by solving one model in the class, TASEP, and passing to the limit. Both TASEP and the KPZ fixed point turn out to have a novel structure: "stochastic integrable systems" (Joint work with Konstantin Matetski and Daniel Remenik).
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Seminar Information Pages

Note for Attendees
The seminar is followed by PIMS tea at 3:45pm