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BEGIN:VEVENT
SUMMARY:Yaping Wu (Capital Normal University)
DTSTART:20200803T130000Z
DTEND:20200803T133000Z
DTSTAMP:20260422T185530Z
UID:BIRS_20w5205/1
DESCRIPTION:Title: The spectral stability of bacteria pulse wave for a Keller-Segel chem
otactic model\nby Yaping Wu (Capital Normal University) as part of BIR
S workshop: Interfacial Phenomena in Reaction-Diffusion Systems\n\n\nAbstr
act\nIn this talk we shall talk about our recent work on the spectral stab
ility/instability of the whole family of explicit traveling waves $(B(x-ct
)\,S(x-ct))$ in some weighted spaces\, by applying detailed spectral ana
lysis\, Evan's function method and numerical simulation. We shall also tal
k about our work on the local well-posedness of solution for the original
Keller-Segel model \\eqref{KS}.\n\nIt's a joint work with Yi Li\, Yong Li
and Hao Zhang.\n
LOCATION:https://researchseminars.org/talk/BIRS_20w5205/1/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Quentin Griette (University of Bordeaux)
DTSTART:20200803T134000Z
DTEND:20200803T141000Z
DTSTAMP:20260422T185530Z
UID:BIRS_20w5205/2
DESCRIPTION:Title: Sharp discontinuous traveling waves in a hyperbolic Keller–Segel eq
uation\nby Quentin Griette (University of Bordeaux) as part of BIRS wo
rkshop: Interfacial Phenomena in Reaction-Diffusion Systems\n\n\nAbstract\
nThis talk concerns a hyperbolic model of cell-cell repulsion with a dynam
ics in the population of cells. More precisely\, we consider a population
of cells producing a field (the “pressure”) which induces a motion of
the cells following the opposite of the gradient. The field indicates the
local density of population and we assume that cells try to avoid crowded
areas and prefer locally empty spaces which are far away from the carrying
capacity. We analyze the well-posedness property of the associated Cauchy
problem on the real line. We start from bounded initial conditions and we
consider some invariant properties of the initial conditions such as the
continuity\, smoothness and monotony. We also describe in detail the behav
ior of the level sets near the propagating boundary of the solution and we
find that an asymptotic jump is formed on the solution for a natural clas
s of initial conditions. Finally\, we prove the existence of sharp traveli
ng waves for this model\, which are particular solutions traveling at a co
nstant speed\, and argue that sharp traveling waves are necessarily discon
tinuous. This analysis is confirmed by numerical simulations of the PDE pr
oblem. \n\nThis is a joint work with Xiaoming Fu and Pierre Magal.\n
LOCATION:https://researchseminars.org/talk/BIRS_20w5205/2/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Xing Liang (University of Science and Technology of China)
DTSTART:20200803T142000Z
DTEND:20200803T145000Z
DTSTAMP:20260422T185530Z
UID:BIRS_20w5205/3
DESCRIPTION:Title: Spreading speeds of nonlocal diffusion KPP equations\nby Xing Lia
ng (University of Science and Technology of China) as part of BIRS worksho
p: Interfacial Phenomena in Reaction-Diffusion Systems\n\nAbstract: TBA\n
LOCATION:https://researchseminars.org/talk/BIRS_20w5205/3/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Thomas Giletti (University of Lorraine)
DTSTART:20200804T130000Z
DTEND:20200804T133000Z
DTSTAMP:20260422T185530Z
UID:BIRS_20w5205/4
DESCRIPTION:Title: Propagating terraces in multidimensional and spatially periodic domai
ns\nby Thomas Giletti (University of Lorraine) as part of BIRS worksho
p: Interfacial Phenomena in Reaction-Diffusion Systems\n\n\nAbstract\nThis
talk will be devoted to the existence of pulsating travelling front solut
ions for spatially periodic heterogeneous reaction-diffusion equations in
arbitrary dimension\, in the multistable case. In general\, the notion of
a single front is not sufficient to understand the dynamics of solutions\,
and we instead observe the appearance of a so-called propagating terrace.
This roughly refers to a finite family of stacked fronts connecting inter
mediate stable steady states and whose speeds are ordered. Surprisingly\,
for a given equation\, the shape of this terrace (i.e.\, the involved inte
rmediate steady states or even their number) may depend on the direction o
f the propagation. This in turn raises some difficulties in the spreading
shape of solutions of the evolution problem. The presented results come fr
om a series of collaborations with W. Ding\, A. Ducrot\, H. Matano and L.
Rossi.\n
LOCATION:https://researchseminars.org/talk/BIRS_20w5205/4/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Nao Hamamuki (Hokkaido University)
DTSTART:20200804T133000Z
DTEND:20200804T140000Z
DTSTAMP:20260422T185530Z
UID:BIRS_20w5205/5
DESCRIPTION:Title: Asymptotic behavior of solutions to level-set mean curvature flow equ
ations with discontinuous source terms\nby Nao Hamamuki (Hokkaido Univ
ersity) as part of BIRS workshop: Interfacial Phenomena in Reaction-Diffus
ion Systems\n\n\nAbstract\nMotivated by the two-dimensional nucleation of
crystal growth\,\nwe consider the initial-value problem of the level-set m
ean curvature flow equation with discontinuous source terms.\n\nWe discuss
uniqueness and existence of viscosity solutions and study the asymptotic
shape of solutions. Applying the game-theoretic interpretation for this pr
oblem\, we also study the asymptotic speed of solutions.\n\nThis talk is b
ased on a joint work with K. Misu (Hokkaido University).\n
LOCATION:https://researchseminars.org/talk/BIRS_20w5205/5/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Samuel Nordmann (University of Tel-Aviv)
DTSTART:20200804T140000Z
DTEND:20200804T143000Z
DTSTAMP:20260422T185530Z
UID:BIRS_20w5205/6
DESCRIPTION:Title: The symmetry of stable solutions of semilinear elliptic equations
\nby Samuel Nordmann (University of Tel-Aviv) as part of BIRS workshop: In
terfacial Phenomena in Reaction-Diffusion Systems\n\n\nAbstract\nConsider
a general semilinear elliptic equation with Neumann boundary conditions. A
seminal result of Casten\, Holland (1978) and Matano (1979) states that\,
if the domain is convex and bounded\, any stable solution is constant. In
this talk\, we will investigate whether this classification result extend
s to convex unbounded domains\, or to some non-convex domains. These quest
ions involve the geometry of the domain in a rather intricate way. In part
icular\, our results recover and extend some classical results on De Giorg
i's conjecture about the classification of stable solutions of the Allen-C
ahn equation in $R^n$.\n
LOCATION:https://researchseminars.org/talk/BIRS_20w5205/6/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Cole Graham (Stanford University)
DTSTART:20200804T143000Z
DTEND:20200804T150000Z
DTSTAMP:20260422T185530Z
UID:BIRS_20w5205/7
DESCRIPTION:Title: Reaction-diffusion equations in the half-space\nby Cole Graham (S
tanford University) as part of BIRS workshop: Interfacial Phenomena in Rea
ction-Diffusion Systems\n\n\nAbstract\nThe interplay between reaction-diff
usion evolution and spatial boundary has received a great deal of recent a
ttention. In this talk\, we consider an essential example: reaction-diffus
ion equations in the half-space. Using the maximum principle and the slidi
ng method\, we handle a host of reactions (monostable\, ignition\, and bis
table) under a wide class of boundary conditions (Dirichlet and Robin). We
consider the existence and uniqueness of steady states\, the asymptotic s
peed of propagation\, and the existence of traveling waves. This is joint
work with Henri Berestycki.\n
LOCATION:https://researchseminars.org/talk/BIRS_20w5205/7/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Ryunosuke Mori (Meiji University)
DTSTART:20200805T130000Z
DTEND:20200805T133000Z
DTSTAMP:20260422T185530Z
UID:BIRS_20w5205/8
DESCRIPTION:Title: Mathematical Analysis of a Reaction-Diffusion Model for Neolithic Tra
nsition in Europe\nby Ryunosuke Mori (Meiji University) as part of BIR
S workshop: Interfacial Phenomena in Reaction-Diffusion Systems\n\n\nAbstr
act\nIn 1996\, Aoki\, Shida and Shigesada proposed a three-component react
ion-diffusion model describing the spread of the early farming during the
New Stone Age. By numerical simulations and some formal linearization argu
ments\, they concluded that there are four different types of spreading be
haviors depending on the parameter values.\n\nIn this talk\, we give theor
etical justification to all of the four types of spreading behaviors obser
ved by Aoki et al. We also investigate the case where the motility of the
hunter-gatherers is not equal to that of the farmers\, which is not discus
sed in the paper of Aoki et al.\n
LOCATION:https://researchseminars.org/talk/BIRS_20w5205/8/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Chang-Hong Wu (National Chiao Tung University)
DTSTART:20200805T134000Z
DTEND:20200805T141000Z
DTSTAMP:20260422T185530Z
UID:BIRS_20w5205/9
DESCRIPTION:Title: Wave Propagation in Two-Species Strong Competition Models\nby Cha
ng-Hong Wu (National Chiao Tung University) as part of BIRS workshop: Inte
rfacial Phenomena in Reaction-Diffusion Systems\n\n\nAbstract\nWave propag
ation for the two-species Lotka-Volterra competition models has been studi
ed widely. In this talk\, we shall focus on the bistable waves and discuss
some recent progress.\n
LOCATION:https://researchseminars.org/talk/BIRS_20w5205/9/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Wenxian Shen (Auburn University)
DTSTART:20200805T143000Z
DTEND:20200805T150000Z
DTSTAMP:20260422T185530Z
UID:BIRS_20w5205/10
DESCRIPTION:Title: Can chemotaxis speed up or slow down the spatial spreading in parabo
lic-elliptic Keller-Segel systems with logistic source?\nby Wenxian Sh
en (Auburn University) as part of BIRS workshop: Interfacial Phenomena in
Reaction-Diffusion Systems\n\nAbstract: TBA\n
LOCATION:https://researchseminars.org/talk/BIRS_20w5205/10/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Masahiko Shimojo (Okayama University of Sciences)
DTSTART:20200806T130000Z
DTEND:20200806T133000Z
DTSTAMP:20260422T185530Z
UID:BIRS_20w5205/11
DESCRIPTION:Title: Convergence to traveling wave for the logarithmic diffusion equation
with reaction term\nby Masahiko Shimojo (Okayama University of Scienc
es) as part of BIRS workshop: Interfacial Phenomena in Reaction-Diffusion
Systems\n\nAbstract: TBA\n
LOCATION:https://researchseminars.org/talk/BIRS_20w5205/11/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Maolin Zhou (Nankai University)
DTSTART:20200806T133000Z
DTEND:20200806T140000Z
DTSTAMP:20260422T185530Z
UID:BIRS_20w5205/12
DESCRIPTION:Title: The principal eigenvalue problem for some second order elliptic and
parabolic operators with large advection\nby Maolin Zhou (Nankai Unive
rsity) as part of BIRS workshop: Interfacial Phenomena in Reaction-Diffusi
on Systems\n\n\nAbstract\nIn this talk\, we will show some recent results
about the limit problem of the principal eigenvalue for some second ellipt
ic and parabolic operators in one dimensional space when the advection coe
fficient converges to infinity. It has some applications to the existence
and stability of solutions of single equations and systems. This is a join
t work with Shuang Liu\, Yuan Lou and Rui Peng.\n
LOCATION:https://researchseminars.org/talk/BIRS_20w5205/12/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Harunori Monobe (Okayama University)
DTSTART:20200806T140000Z
DTEND:20200806T143000Z
DTSTAMP:20260422T185530Z
UID:BIRS_20w5205/13
DESCRIPTION:Title: Fast reaction limit of three-components reaction-diffusion systems a
nd free boundary problems describing population dynamics\nby Harunori
Monobe (Okayama University) as part of BIRS workshop: Interfacial Phenomen
a in Reaction-Diffusion Systems\n\nAbstract: TBA\n
LOCATION:https://researchseminars.org/talk/BIRS_20w5205/13/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Léo Girardin (University of Paris-Sud)
DTSTART:20200806T143000Z
DTEND:20200806T150000Z
DTSTAMP:20260422T185530Z
UID:BIRS_20w5205/14
DESCRIPTION:Title: Strong competition limit\, traveling waves and best dispersal strate
gy for Lotka-Volterra competitive systems\nby Léo Girardin (Universit
y of Paris-Sud) as part of BIRS workshop: Interfacial Phenomena in Reactio
n-Diffusion Systems\n\n\nAbstract\nIn this talk\, I will present an ongoin
g work in collaboration with\nDanielle Hilhorst about the singular limit o
f a large class of\nstrongly coupled\, strongly competitive two-species re
action--diffusion \nsystems. Particular cases are the standard Lotka--Volt
erra system\, the\nPotts--Petrovskii cross-taxis system and the SKT cross-
diffusion system. \nWe focus on the singular limit of traveling waves and
use the sign of\nthe wave speed as a criterion to compare dispersal--growt
h strategies.\n
LOCATION:https://researchseminars.org/talk/BIRS_20w5205/14/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Jean-Michel Roquejoffre (Universite Paul Sabatier)
DTSTART:20200807T130000Z
DTEND:20200807T133000Z
DTSTAMP:20260422T185530Z
UID:BIRS_20w5205/15
DESCRIPTION:Title: Properties of a free boundary driven by a line of fast diffusion
\nby Jean-Michel Roquejoffre (Universite Paul Sabatier) as part of BIRS wo
rkshop: Interfacial Phenomena in Reaction-Diffusion Systems\n\n\nAbstract\
nThe situation is the following: a line\, having a strong diffusion on its
own\,\nexchanges mass with the half plane below\, supposed to be a reacti
ve medium. A front propagates\nboth on the line and below\, and one wishes
to describe its shape. This setting was proposed\n(collaboration with H.
Berestycki and L. Rossi) as a model of how biological invasions can be\nen
hanced by transportation networks.\n\nNumerical simulations\, due to A.-C.
Coulon\, reveal an a priori surprising phenomenon:\nthe solution is not m
onotone in the direction orthogonal to the line. We will try to\nunderstan
d this feature in the particular case of a free boundary problem that can
be\nobtained as a limiting case of the original reaction-diffusion system\
, amd discuss\nfurther features of the free boundary\, such as its shape a
t infinity\, or what happens when the\ndiffusion on the line becomes infin
ite.\n\nJoint work with L. Caffarelli.\n
LOCATION:https://researchseminars.org/talk/BIRS_20w5205/15/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Changfeng Gui (University of Texas at San Antonio)
DTSTART:20200807T134000Z
DTEND:20200807T141000Z
DTSTAMP:20260422T185530Z
UID:BIRS_20w5205/16
DESCRIPTION:Title: Propagation acceleration in reaction diffusion equations with a frac
tional Laplacian\nby Changfeng Gui (University of Texas at San Antonio
) as part of BIRS workshop: Interfacial Phenomena in Reaction-Diffusion Sy
stems\n\n\nAbstract\nIn this talk\, I will present recent results on the
propagation speed in a reaction diffusion system with an anomalous Levy
process diffusion\, modeled by a nonlocal equation with a fractional La
placian and a generalized KPP type monostable nonlinearity. Given a typi
cal Heavy side initial datum\, we show that the speed of interface propa
gation displays an algebraic rate behavior in time\, in contrast to the
known linear rate in the classical model of Brownian motion and the exp
onential rate in the KPP model with the anomalous diffusion\, and depends
on the sensitive balance between the anomaly of the diffusion process and
the strength of monostable reaction. In particular\, for the combust
ion model with\na fractional Laplacian $(-\\Delta)^{s}$\, we show that t
he speed of propagation transits continuously from being linear in time\
, when a traveling wave solution exists for $s \\in (1/2\, 1)$\, to bein
g algebraic in time with a power reciprocal to $2s$\, when no traveling
wave solution exists for $s \\in (0\, 1/2)$.\n\n The talk is based on a
joint work with Jerome Coville and Mingfeng Zhao.\n
LOCATION:https://researchseminars.org/talk/BIRS_20w5205/16/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Sigurd Angenent (University of Wisconsin)
DTSTART:20200807T142000Z
DTEND:20200807T145000Z
DTSTAMP:20260422T185530Z
UID:BIRS_20w5205/17
DESCRIPTION:Title: Dynamics of convex mean curvature flow\nby Sigurd Angenent (Univ
ersity of Wisconsin) as part of BIRS workshop: Interfacial Phenomena in Re
action-Diffusion Systems\n\n\nAbstract\nMean Curvature Flow defines a grad
ient-like dynamical system on the space of convex hypersurfaces. I will d
iscuss what is known about the fixed points and connecting orbits of this
flow.\n
LOCATION:https://researchseminars.org/talk/BIRS_20w5205/17/
END:VEVENT
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