BEGIN:VCALENDAR
PRODID:-//PSU Mathematics Department//Seminar iCalendar Generator//EN
VERSION:2.0
CALSCALE:GREGORIAN
METHOD:PUBLISH
X-WR-CALNAME:Department of Mathematics Colloquium
X-WR-TIMEZONE:America/New_York
BEGIN:VTIMEZONE
TZID:America/New_York
X-LIC-LOCATION:America/New_York
BEGIN:DAYLIGHT
TZOFFSETFROM:-0500
TZOFFSETTO:-0400
TZNAME:EDT
DTSTART:19700308T020000
RRULE:FREQ=YEARLY;BYMONTH=3;BYDAY=2SU
END:DAYLIGHT
BEGIN:STANDARD
TZOFFSETFROM:-0400
TZOFFSETTO:-0500
TZNAME:EST
DTSTART:19701101T020000
RRULE:FREQ=YEARLY;BYMONTH=11;BYDAY=1SU
END:STANDARD
END:VTIMEZONE
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20150827T153500
DTEND;TZID=America/New_York:20150827T162500
LOCATION:MB114
URL:http://www.math.psu.edu/seminars/meeting.php?id=25670
SUMMARY:Department of Mathematics Colloquium - TBA
DESCRIPTION:Seminar: Department of Mathematics Colloquium\nTitle: TBA
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20150903T153500
DTEND;TZID=America/New_York:20150903T162500
LOCATION:MB114
URL:http://www.math.psu.edu/seminars/meeting.php?id=25672
SUMMARY:Department of Mathematics Colloquium - Departmental Reception
DESCRIPTION:Seminar: Department of Mathematics Colloquium\nTitle: Departmen
tal Reception\nSpeaker: Departmental Reception
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20150910T153500
DTEND;TZID=America/New_York:20150910T162500
LOCATION:MB114
URL:http://www.math.psu.edu/seminars/meeting.php?id=25674
SUMMARY:Department of Mathematics Colloquium - Faculty Meeting
DESCRIPTION:Seminar: Department of Mathematics Colloquium\nTitle: Faculty M
eeting\nSpeaker: Faculty Meeting
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20150917T153500
DTEND;TZID=America/New_York:20150917T162500
LOCATION:MB114
URL:http://www.math.psu.edu/seminars/meeting.php?id=28115
SUMMARY:Department of Mathematics Colloquium - Hyperfields
DESCRIPTION:Seminar: Department of Mathematics Colloquium\nTitle: Hyperfiel
ds\nSpeaker: Oleg Viro - Joint MASS Speaker (Host: Sergei Tabachnikov)\,
Stony Brook University\nAbstract: In order to define hyperfields\, one sho
uld allow in the definition of field the addition to be multivalued and ad
just the axioms minimally. Hyperfields are not just exotic creatures produ
ced by this abstract play with axioms. They appear naturally and pervade s
ecretly the whole classical mathematics. For example\, triangle inequaliti
es describe a multivalued addition of non-negative real numbers. Equipped
with this addition and the usual multiplication\, this set is a hyperfield
. Multiplicative norms in a ring are nothing but homomorphisms to this hyp
erfield. Hyperfields appear as natural quotient sets of fields and as dequ
antizations of fields (degenerate members in continuous families of fields
). Mysterious fields of characteristic one may be hyperfields. Hyperfields
provide an algebraic framework for the tropical\ngeometry\, a dequantized
algebraic geometry.
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20150924T153500
DTEND;TZID=America/New_York:20150924T162500
LOCATION:MB114
URL:http://www.math.psu.edu/seminars/meeting.php?id=25678
SUMMARY:Department of Mathematics Colloquium - Harmonic functions on graphs
and rectangular tilings of a square
DESCRIPTION:Seminar: Department of Mathematics Colloquium\nTitle: Harmonic
functions on graphs and rectangular tilings of a square\nSpeaker: Aaron Ab
rams - Joint MASS Speaker (Host: Sergei Tabachnikov)\, Washington and Lee
University\nAbstract: The classical Dirichlet problem is to find a harmon
ic function on a space with specified boundary values.\nOn a network with
two boundary vertices and fixed edge conductances\, the solution can be in
terpreted as\ngiving the energies associated to a current flow on the netw
ork\, or as the sizes of the rectangles in a tiling \nof a square. \n\nWe
study the inverse problem: for any choice of edge energies\, we show tha
t there is always a choice of \nconductances for which the corresponding h
armonic function realizes the given energies. In fact the set of \nsoluti
ons is in correspondence with the acyclic orientations of the network. As
a result\, if the initial inputs \nare rational then the totally real Gal
ois group acts on the set of acyclic orientations of the network.
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20151001T153500
DTEND;TZID=America/New_York:20151001T162500
LOCATION:MB114
URL:http://www.math.psu.edu/seminars/meeting.php?id=25676
SUMMARY:Department of Mathematics Colloquium - HIGH=FREQUENCY STABILITY OF
DETONATION WAVES AND BLOCK DIAGONALIZATION OF ODES
DESCRIPTION:Seminar: Department of Mathematics Colloquium\nTitle: HIGH=FREQ
UENCY STABILITY OF DETONATION WAVES AND BLOCK DIAGONALIZATION OF ODES\nSp
eaker: Kevin Zumbrun (Host: Toan Nguyen)\, Indiana University (joint work
with Olivier Lafitte\, Paris 13\, and Mark Williams\, UNC)\nAbstract: A
delicate aspect of numerical stability investigations for \nZND (inviscid)
detonations is truncation of the computational domain via \nhigh-frequenc
y asymptotics\, amounting to an ordinary differential \nsemi-classical lim
it problem $h(dW/dx)=A(x\,h)W$\, where $h>0$ is a small \nparameter tendin
g toward $0^+$. This leads to interesting and general \nquestions related
to WKB expansion\, turning points\, and \nblock-diagonalization/separatio
n of modes. In particular\, as we shall \ndescribe\, it highlights the di
stinction between ``spectral gap'' and \n``spectral separation'' in asympt
otic ODE theory\, revealing essential \ndifferences between C- infinity c
oefficient and analytic coefficient \ntheory. These differences are in tu
rn related to oscillatory integrals \nand differences in stationary phase
estimates for C infinity vs. \nanalytic symbols. The results we describe a
re an essential part of our \nrecent proof of high-frequency detonation st
ability\, completing a \nprogram pioneered by J.J. Erpenbeck in the 1960's
. However\, no \nknowledge of detonation theory is assumed in the talk an
d the analysis\, \nthough motivated by physical considerations\, concerns
basic questions in \nasymptotic ordinary differential equations.
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20151008T153500
DTEND;TZID=America/New_York:20151008T162500
LOCATION:MB114
URL:http://www.math.psu.edu/seminars/meeting.php?id=25682
SUMMARY:Department of Mathematics Colloquium - Dimension\, K-theory and rig
idity
DESCRIPTION:Seminar: Department of Mathematics Colloquium\nTitle: Dimension
\, K-theory and rigidity\nSpeaker: Guoliang Yu (Host: Nigel Higson)\, Texa
s A&M\nAbstract: I will introduce a concept of dynamic dimension for group
actions and explain how it can be used to compute K-theory and study the
rigidity of manifolds. This is joint work with Erik Guentner\, Rufus Wille
tt\, and Zhizhang Xie. The talk will be accessible to graduate students.
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20151015T153500
DTEND;TZID=America/New_York:20151015T162500
LOCATION:MB114
URL:http://www.math.psu.edu/seminars/meeting.php?id=25684
SUMMARY:Department of Mathematics Colloquium - Arnold's problem\, the Gömb
öc and the evolution of pebble shapes
DESCRIPTION:Seminar: Department of Mathematics Colloquium\nTitle: Arnold's
problem\, the Gömböc and the evolution of pebble shapes\nSpeaker: Gábor
Domokos - Joint MASS Speaker (Host: Sergei Tabachnikov)\, Budapest Univer
sity of Technology and Ecomonics\nAbstract: The best known mathematical mo
dels for the abrasion of sedimentary particles are curvature-driven flows
\, a special class of nonlinear partial differential equations defining t
he evolution of a surface Sigma by the speed v in the direction of its sur
face normal\, and v is a function of the principal curvatures kappa\, lam
bda of Sigma: v=v(kappa\, lambda). \n\nIn 1987 Grayson proved that if Sig
ma is given as a distance function from a fixed reference O then the numbe
r N(t) of spatial critical points (extrema of the distance) is decreasing
monotonically under the planar v=kappa flow. We will show that there is mo
unting evidence that similar\, though weaker (generic\, stochastic) statem
ents are true for static balance points on 3D solids evolving under the ab
ove equation.\n\nOur model predicts that the expected value of the number
of static balance points on abrading solids will decrease monotonically. L
aboratory and field data show a remarkable match with the proposed Markov
process. We will also discuss why Gömböc shapes\, with minimal number o
f balance points\,\nare almost never found in Nature. Rather\, as physicis
t Sir Michael Berry expressed it\,``they exist in Nature only as a dream".
\n\nI will speak on the discovery of the Gömböc in the MASS colloquium.
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20151022T153500
DTEND;TZID=America/New_York:20151022T162500
LOCATION:MB114
URL:http://www.math.psu.edu/seminars/meeting.php?id=25686
SUMMARY:Department of Mathematics Colloquium - Eigenvalues and Eigenvectors
: Numerics\, Dynamics\,Complexity
DESCRIPTION:Seminar: Department of Mathematics Colloquium\nTitle: Eigenvalu
es and Eigenvectors: Numerics\, Dynamics\,Complexity\nSpeaker: Michael Shu
b (Host: Svetlana Katok)\, CUNY Graduate Center\nAbstract: Given an n by n
real or complex matrix M\, find one or all the eigenvalue\, eigenvector p
airs of M. The problem is simple and pervasive\, yet there is no known (
at least by me)numerical algorithm which has a simple list of desired feat
ures: a) stability\, b) convergence with probability one c) average polyno
mial complexity. I will survey some of the problems concerning elimination
theory and dynamical systems which arise. Finally I will present an algor
ithm satisfying all three criteria in the complex case.
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20151029T153500
DTEND;TZID=America/New_York:20151029T162500
LOCATION:MB114
URL:http://www.math.psu.edu/seminars/meeting.php?id=25688
SUMMARY:Department of Mathematics Colloquium - Conformal Tiling --- tiling
in a non-linear world
DESCRIPTION:Seminar: Department of Mathematics Colloquium\nTitle: Conformal
Tiling --- tiling in a non-linear world\nSpeaker: Ken Stephenson - Joint
MASS Speaker (Host: Sergei Tabachnikov)\, University of Tennessee\nAbstra
ct: (Joint work with Phil Bowers\, Florida State) Conformal tilings\nform
a new chapter in the ongoing story of aperiodic heierarchical tilings.\nTh
e most famous and fascinating traditional example is the Penrose tiling\nf
ormed by so-called 'kites' and 'darts'. The new theory\, however\, is non-
linear\; it\nmoves away tiles with rigid euclidean shapes to tiles that ar
e\nconformally regular and get their rigidity from the global pattern. One
sees\nmuch of the richness of the traditional theory\, but also new conne
ctions\nto Cannon\, Floyd\, and Parry's work with subdivision rules\, to G
rothendieck\ndessin d'enfant\, and to theories of emergent structure in ra
ndom triangulations\nand quadrangulations. This talk will be rich with ima
ges. I will discuss the\nfoundations\, but will concentrate on phenomena o
bserved in examples\, including\nthe conformal version of the Penrose tili
ng and a new "Snow Sphere"\, a 2D analogue\nof von Koch's snowflake.
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20151105T153500
DTEND;TZID=America/New_York:20151105T162500
LOCATION:MB114
URL:http://www.math.psu.edu/seminars/meeting.php?id=25690
SUMMARY:Department of Mathematics Colloquium - Cross-immunoreactivity cause
s antigenic cooperation
DESCRIPTION:Seminar: Department of Mathematics Colloquium\nTitle: Cross-imm
unoreactivity causes antigenic cooperation\nSpeaker: Leonid Bunimovich (Ho
st: Yakov Pesin)\, Georgia Tech\nAbstract: Hepatitis C virus (HCV) has th
e propensity to cause chronic infection. HCV affects an estimated 170 mill
ion people worldwide. Immune escape by continuous genetic diversification
is commonly described using a metaphor of "arm race" between virus and hos
t. We developed a mathematical model that explained all clinical observati
ons which could not be explained by the "arm race theory". The model appli
ed to network of cross-immunoreactivity suggests antigenic cooperation as
a mechanism of mitigating the immune pressure on HCV variants. Antigenic c
ooperation is a new target for therapeutic- and vaccine- development strat
egies.\n \nJoint work with P.Skums and Yu. Khudyakov (Center for Disease
Control).
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20151112T153500
DTEND;TZID=America/New_York:20151112T162500
LOCATION:MB114
URL:http://www.math.psu.edu/seminars/meeting.php?id=25692
SUMMARY:Department of Mathematics Colloquium - The Prisoner’s Dilemma: Th
e Emergence of Cooperation
DESCRIPTION:Seminar: Department of Mathematics Colloquium\nTitle: The Priso
ner’s Dilemma: The Emergence of Cooperation\nSpeaker: Enrique Pujals (Ho
st: Federico Rodriguez Hertz)\, IMPA\nAbstract: The tension between oppor
tunistic behavior and cooperation\nis a central features of many human (an
d animal) interactions.\nUnderstanding when people can overcome the incent
ives for\nopportunistic behavior and cooperate with each other is of impor
tance\nfor many sciences\, from Economics to Biology. The literature on\ni
nfinitely repeated games shows how repeated interaction can yield\ncoopera
tion. We will discuss some of the fundamental theoretical\nfindings of thi
s literature\, experimental results with human subjects\nand the applicati
on of dynamics to address the issue of multiplicity\nof equilibria in infi
nitely repeated games.\nThis is joint work with Pedro Dal Bo (Brown Univer
sity).
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20151119T153500
DTEND;TZID=America/New_York:20151119T162500
LOCATION:MB114
URL:http://www.math.psu.edu/seminars/meeting.php?id=25694
SUMMARY:Department of Mathematics Colloquium - Projective rolling\, the dan
cing metric and G2 symmetry
DESCRIPTION:Seminar: Department of Mathematics Colloquium\nTitle: Projectiv
e rolling\, the dancing metric and G2 symmetry\nSpeaker: Gil Bor - Joint M
ASS Speaker (Host: Sergei Tabachnikov)\, Centro de Investigación en Mate
máticas\, Mexico\nAbstract: I will describe a new interaction between thr
ee types of well-known geometries: (1) projective geometry of plane curves
\, (2) split-signature conformal metrics on 4-manifolds\, (3) generic 2-pl
ane distributions on 5 manifolds. (1) and (3) have been studied (separatel
y) more than 100 years ago. (2) and (3) are related via a recent version d
ue to An-Nurowski of Penrose’ twistor construction. The relation between
(1) and (3) reveals an unexpected G2-symmetry\, hidden deep in the class
ical theory of projective plane curves.
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20151126T153500
DTEND;TZID=America/New_York:20151126T162500
LOCATION:MB114
URL:http://www.math.psu.edu/seminars/meeting.php?id=25696
SUMMARY:Department of Mathematics Colloquium - THANKSGIVING BREAK
DESCRIPTION:Seminar: Department of Mathematics Colloquium\nTitle: THANKSGIV
ING BREAK\nSpeaker: THANKSGIVING BREAK
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20151203T153500
DTEND;TZID=America/New_York:20151203T162500
LOCATION:MB114
URL:http://www.math.psu.edu/seminars/meeting.php?id=25698
SUMMARY:Department of Mathematics Colloquium - Faculty Meeting
DESCRIPTION:Seminar: Department of Mathematics Colloquium\nTitle: Faculty M
eeting\nSpeaker: Faculty Meeting
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20151210T103000
DTEND;TZID=America/New_York:20151210T170000
LOCATION:MB114
URL:http://www.math.psu.edu/seminars/meeting.php?id=25700
SUMMARY:Department of Mathematics Colloquium - Staff Appreciation Tea
DESCRIPTION:Seminar: Department of Mathematics Colloquium\nTitle: Staff App
reciation Tea\nSpeaker: Staff Appreciation Tea
END:VEVENT
END:VCALENDAR