ESAIM: COCV
DOI: 10.1051/cocv:2008017
Aubry sets and the differentiability of the minimal average action in codimension one
Ugo BessiDipartimento di Matematica, Università Roma Tre, Largo S. Leonardo Murialdo, 00146 Roma, Italy
(Received November 3, 2006. Revised July 23, 2007. Published online March 6, 2008.)
Abstract
Let
(x,u,
u) be a Lagrangian periodic of period 1 in
x1,
,xn,u. We shall study the non self intersecting
functions u: Rn
R minimizing
; non self intersecting means that, if u(x0 + k) + j = u(x0)
for some x0
Rn and (k , j)
Zn
Z, then
u(x) = u(x + k) + j
x. Moser has shown that each of these
functions is at finite distance from a plane
u =
x and thus
has an average slope
; moreover, Senn has proven that it is
possible to define the average action of u, which is usually called
since it only depends on the slope of u.
Aubry and Senn have noticed a connection between
and the
theory of crystals in Rn+1, interpreting
as the energy per area of a crystal face normal to (-
,1). The polar of
is usually called -
; Senn has shown that
is C1 and that the dimension of the flat of
which contains c depends only on the "rational space" of
(c). We prove a similar result for the faces (or the faces of the faces, etc.) of the flats of
: they are C1 and their dimension depends only on the rational space of their normals.
Mathematics Subject Classification. 35J20, 35J60
Key words: Aubry-Mather theory for elliptic problems, corners of the mean average action
© EDP Sciences, SMAI 2008



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