Donatella
Danielli
Research Interests
My research focuses on the study of analytic and geometric properties of partial differential equations and variational inequalities. More specifically, recently I have been interested in lower dimensional obstacle problems and free boundary problems arising in the theory of flame propagation.
Publications
A compact embedding theorem for a class of degenerate
Sobolev spaces. Rendiconti Sem. Mat. Univ. Polit.
Torino, 49(3); 399-420, 1991.
Formules de representation et theoremes d’inclusion
pour des operateurs sous-elliptiques. Comptes
Rendus Acad. Sci. Paris, t. 314, Serie I; 987-990,
1992.
(with L. Capogna and N. Garofalo)
Embedding theorems and the Harnack inequality for
solutions of nonlinear subelliptic equations.
Comptes Rendus Acad. Sci. Paris, t. 316, Serie I;
809-814, 1993.
(with L. Capogna and N. Garofalo)
An embedding theorem and the Harnack inequality for
nonlinear subelliptic equations. Comm. in PDE,
18; 1765-1794, 1993.
(with L. Capogna and N. Garofalo)
Subelliptic mollifiers and a characterization of Rellich
and Poincaré domains. Rend Sem. Mat. Univ. Polit.
Torino, 51(4); 361-386, 1993.
(with L. Capogna and N. Garofalo)
An isoperimetric inequality and the geometric Sobolev
embedding for vector fields. Mathematical
Research Letters, 1; 263-268, 1994.
(with L. Capogna and N. Garofalo)
The geometric Sobolev embedding for vector fields and the
isoperimetric inequality. Comm. in Analysis
and Geometry, 2(2); 203-215, 1994.
Regularity at the boundary for solutions of nonlinear
subelliptic equations. Indiana Univ. Math. J.,
44(1); 269-286, 1995.
(with L. Capogna and N. Garofalo)
Capacitary estimates and the local behavior of solutions
of nonlinear subelliptic equations. Amer. Jour.
Mathematics, 118(6) 1153-1196, 1996.
(with L. Capogna and N. Garofalo)
Subelliptic mollifiers and a basic pointwise estimate of
Poincaré type. Math. Zeitschrift, 226; 147-154,
1997.
(with N. Garofalo)
Geometric properties of solutions to subelliptic equations
in nilpotent Lie groups. Lecture Notes in Pure and
Applied Mathematics, vol.194, Reaction
Diffusion Systems, Marcel Dekker Inc., 89-105, 1998.
(with N. Garofalo and D. M. Nhieu)
Isoperimetric and trace inequalities with respect to
Carnot-Carathéodory metrics. Geometry
Seminars, 1996-97, Univ. of Bologna, Bologna, 51-62,
1998.
(with N. Garofalo and D. M. Nhieu)
Trace inequalities for Carnot-Carathéodory spaces
and applications. Annali Scuola Normale Sup.
Pisa (4), 27; 195-252, 1998.
A
Fefferman-Phong type inequality and applications to
quasilinear subelliptic equations. Potential
Analysis, 11 (4); 387-413, 1999.
(with N. Garofalo and D. M. Nhieu)
Sub-elliptic Besov spaces and the characterization of
traces on lower dimensional manifolds.
Contemporary Mathematics, vol. 277, Amer. Math. Soc.,
19-37, 2001.
(with N. Garofalo)
Properties
of entire solutions of non-uniformly elliptic equations
arising in geometry and in phase transitions.
Calculus of Variations, 15 (4); 451-491, 2002.
(with N. Garofalo and S. Salsa)
Variational inequalities with lack of ellipticity. Part I:
interior regularity and non-degeneracy of the free
boundary, Indiana Univ. Math. Jour., 52;
361-398, 2003.
(with A. Petrosyan and H. Shahgholian)
A singular perturbation problem for the p-Laplace
operator,
Indiana Univ. Math. Jour., 52; 457-476, 2003.
(with N. Garofalo and D. M. Nhieu)
On the best possible character of the LQ norm
in some a priori estimates for non-divergence form
equations in Carnot groups, Proc. Amer. Math. Soc.,
131; 3487-3498, 2003.
(with N. Garofalo and D. M. Nhieu)
Notions of convexity in Carnot groups, Comm. Anal.
Geom., 11 (2); 263-341, 2003.
(with N. Garofalo, D. M. Nhieu, and F. Tournier)
The Theorem of Busemann-Feller-Alexandrov in Carnot Groups,
Comm. Anal. Geom., 12 (4); 853-886, 2004.
(with A. Petrosyan)
A minimum problem with free boundary for a degenerate
quasilinear operator, Calculus of Variations,
23 (1); 97-124, 2005.
(with M. Korten)
On
the pointwise jump condition of the free boundary in the
1-phase Stefan problem, Comm. Pure Appl. Anal.,
4 (2), 357-366, 2005.
(with N. Garofalo and D. M. Nhieu)
Non-doubling Ahlfors measures, perimeter measures, and the
characterization of the trace spaces of Sobolev functions
in Carnot-Carathéodory spaces,
Memoirs AMS.,
182 (857), 2006.
(with A. Petrosyan)
Full regularity of the free boundary in a Bernoulli-type
problem in two dimensions,
Math. Res. Lett.,
13 (4), 667-681, 2006.
(with N. Garofalo and A. Petrosyan)
The sub-elliptic obstacle problem: C1,α
regularity of the free boundary in Carnot groups of step
two, Adv. Math., 211, 485-516, 2007.
(with L. Capogna, S. Pauls, and J. Tyson)
An Introduction to the Heisenberg Group and the
sub-Riemannian Isoperimetric Inequality, Progress
in Mathematics, 259. Birkhäuser Verlag, Basel, 2007.
(Editor)
Recent Developments in Nonlinear Partial Differential
Equations, Contemporary Mathematics. Amer.
Math. Soc., 2007.
(with N. Garofalo and D. M. Nhieu)
Sub-Riemannian Calculus on Hypersurfaces in Carnot Groups,
Adv. Math., 215 (1), 292-378, 2007.
(with N. Garofalo and D. M. Nhieu) A
partial solution of the isoperimetric problem for the
Heisenberg group, Forum Mathematicum, 20(1),
99-143, 2008.
(with N. Garofalo and D. M. Nhieu)
A notable family of entire intrinsic minimal graphs in the
Heisenberg group which are not perimeter minimizing, Amer.
Jour. Math., 130 (2), 317-339, 2008.
(with N. Garofalo)
Interior Cauchy-Schauder estimates for the heat flow in
Carnot- Carathéodory
spaces, Methods Appl. Anal., 15 (1) (Special
issue dedicated to N. Trudinger), 121-136, 2008.
(with N. Garofalo, D. M. Nhieu, and S. Pauls),
Instability of graphical strips and a positive answer to
the Bernstein problem in the Heisenberg group,
Jour. Diff. Geom., 81 (2), 251-296, 2009.
(with N. Garofalo and P. C. Nguyen)
Inequalities of Hardy-Sobolev Type in Carnot- Carathéodory
Spaces, Sobolev Spaces in Mathematics I (V. Maz’ya
ed.), International Mathematical Series, Vol. 8, Springer,
117-152, 2009.
(with N. Garofalo and N. Marola)
Local behavior of
p-harmonic
Green's functions in metric spaces,
Potential Anal., 32 (4), 343-362, 2010.
(with N. Garofalo and D. M. Nhieu)
Sub-Riemannian calculus and monotonicity of the perimeter
for graphical strips,
Math. Zeit.,
265 (3), 617-637, 2010.
(with N. Garofalo, D. M. Nhieu, and S. Pauls)
The Bernstein
problem for embedded surfaces in the Heisenberg group
$\Bbb H^1$H1,
Indiana Univ. Math. Jour.,
59 (2), 563-594,
2010.
(with
N. Garofalo and P.C. Nguyen)
Sharp Hardy-Sobolev type inequalities in Carnot-
Carathéodory spaces.
Potential Analysis,
34 (3), 223-242, 2011.
(with N. Garofalo and D.M. Nhieu)
Integrability of the sub-Riemannian mean curvature of
surfaces in the Heisenberg group.
Proc. AMS.,
140, 811-821, 2012.
(with N. Garofalo, A. Petrosyan, and T. To)
Optimal
regularity and the free boundary in the parabolic
Signorini problem.
Memoirs AMS, 249
(1181), 103 p., 2017.
(with S. Salsa)
Obstacle problems involving the fractional Laplacian.
Recent Developments in the Nonlocal Theory (T. Kuusi and G.
Palatucci, Eds.), Book Series on Measure Theory, De
Gruyter, Berlin, 81-164, 2018.
(with A. Petrosyan and C. Pop) Obstacle problems for nonlocal operators. New developments in the analysis of nonlocal operators, 191–214, Contemp. Math., vol. 723, Amer. Math. Soc., 2019.
(with A. Petrosyan, and C. Pop) Obstacle problems for nonlocal operators: A brief overview, To appear in ISNPS 2018 Proceedings. arXiv:1807.10910
(with A. Banerjee, N. Garofalo, and A. Petrosyan) The structure of the singular set in the thin obstacle problem for degenerate parabolic equations. arXiv:1902.07457
(with A. Banerjee, N. Garofalo, and A. Petrosyan) The regular free boundary in the thin obstacle problem for degenerate parabolic equations. arXiv:1906.06885
(with T. Backing and R.
Jain) Regularity results for a penalized boundary obstacle
problem, in preparation.