- A-priori estimates of Carleman's type in domains with
boundary
Journal
des Mathematiques Pures et Appliquees, 73 (1994) 355-387.
- Unique continuation for P.D.E's: between Holmgren's theorem
and
Hormander's
theorem, Communications in Partial Differential Equations, 20
(1995),
855-884
- Carleman estimates and unique continuation for solutions to
boundary-value
problems Journal des Mathematiques Pures et Appliques 75, 1996, p
367-408
- Carleman estimates, unique continuation and controllability
for
anizotropic
pde's , in Optimization Methods in Partial Diff. Equ.,
Contemporary
Mathematics 209 (AMS), 1997, 267-281
- Unique continuation for partial differential operators with
partially
analytic coefficients. J. Math.
Pures Appl. (9) 78 (1999), no. 5,
505--521.
This article considers the unique continuation problem for operators
whose
coefficients depend analytically on some of the variables. The results
in here were first proved in [2] above under certain technical
assumptions.
Part of these assumptions were removed meanwhile by Hormander and
Robbiano-Zuily.
The goal of this article is to remove the remaining technical
assumptions
and, at the same time, to considerably simplify the proof of the result.
- Uniqueness and Stability in the Cauchy problem for Maxwell
and
elasticity
systems Nonlinear partial differential equations
and their
applications. Collège de France Seminar, Vol. XIV (Paris,
1997/1998), 329--349, Stud. Math. Appl., 31. The aim of
this
article is to show how the methods and results
in unique continuation can be applied to Maxwell's equations and to
isotropic
elasticity. Available in dvi-letter
and ps-letter
.
-
On the regularity of boundary traces for the wave equation, Ann.
Scuola Norm. Sup. Pisa Cl. Sci. (4) 26 (1998), no. 1, 185--206. Availlable
in dvi-letter , ps-letter
format.
Carleman estimates, unique continuation and applications This
contains
some notes on unique continuation and (L2) Carleman estimates. It is
fairly
long (136 pages) but unfinished, so use it at you own risk :-). In time
I plan to revise/complete it, add Lp estimates and, perhaps, put it in
a web-friendly format. Available in pdf-letter
and ps-letter
Carleman estimates and boundary observability for a coupled
parabolic-hyperbolic
system (joint with Paolo Albano). This paper studies a problem of
boundary
observability for a coupled system of parabolic-hyperbolic type. First,
we prove some Carleman estimates with singular weights for the heat and
for the wave equations. Then we combine these results to obtain an
observability
result for the system. EJDE
Vol. 2000(2000), No. 22, pp. 1-15
Null controllability for the dissipative semilinear heat
equation. (joint
with Sebastian Anita) Appl.
Math. Optim. 46
(2002), no. 2-3, 97--105. No Carleman estimates here, but
I
didn't
find a better place for it. We consider the exact null controllability
problem for the semilinear heat equation with a dissipative
nonlinearity
in a bounded domain of Rn. The main result of the article asserts that
if the nonlinearity is even mildly superlinear then global null
controllability
in arbitrarily short time fails; instead we provide sharp estimates for
the controllability time in terms of the size of the initial data.
Available
in ps-letter
.
Unique continuation for pde's. The IMA Volumes in
Mathematics and its Applications 137, 239-255, 2003. This is
a
short expository
article whose aim is to provide an overview of the most common types of
problems and results in unique continuation. The $L^2$ Carleman
estimates
are motivated and discussed in each case. I also tried to track back
the
origin of the problems. Available in dvi-letter
and ps-letter
Strong uniqueness for second
order elliptic operators with Gevrey coefficients. (joint with
F. Colombini and C. Grammatico) We consider the question of strong
unique continuation in Gevrey classes for second order elliptic
operators with complex coefficients. The Gevrey index is connected to
the angular spread of the range of the principal symbol. Available in pdf-letter.