1. CJM Online first
 Karpukhin, Mikhail A.

Steklov problem on differential forms
In this paper we study spectral properties of the DirichlettoNeumann
map on differential forms obtained by a slight modification of
the definition due to Belishev and Sharafutdinov.
The
resulting operator $\Lambda$ is shown to be selfadjoint on the
subspace of coclosed forms and to have purely discrete spectrum
there.
We investigate properties of eigenvalues of $\Lambda$ and prove
a HerschPayneSchiffer type inequality relating products of
those eigenvalues to eigenvalues of the Hodge Laplacian on the
boundary. Moreover, nontrivial eigenvalues of $\Lambda$ are
always at least as large as eigenvalues of the DirichlettoNeumann
map defined by Raulot and Savo
Finally, we remark
that a particular case of $p$forms on the boundary of a $2p+2$dimensional
manifold shares a lot of important properties with the classical
Steklov eigenvalue problem on surfaces.
Keywords:DirichlettoNeumann map, differential form, Steklov eigenvalue, shape optimization Categories:58J50, 58J32, 35P15 

2. CJM Online first
 Georgescu, Magdalena Cecilia

Integral Formula for Spectral Flow for $p$Summable Operators
Fix a von Neumann algebra $\mathcal{N}$ equipped with a suitable trace
$\tau$. For a path of selfadjoint BreuerFredholm operators, the
spectral flow measures the net amount of spectrum which moves from
negative to nonnegative. We consider specifically the case of paths
of bounded perturbations of a fixed unbounded selfadjoint
BreuerFredholm operator affiliated with $\mathcal{N}$. If the unbounded
operator is psummable (that is, its resolvents are contained in the
ideal $L^p$), then it is possible to obtain an integral formula which
calculates spectral flow. This integral formula was first proven by
Carey and Phillips, building on earlier approaches of Phillips. Their
proof was based on first obtaining a formula for the larger class of
$\theta$summable operators, and then using Laplace transforms to
obtain a psummable formula. In this paper, we present a direct proof
of the psummable formula, which is both shorter and simpler than
theirs.
Keywords:spectral flow, $p$summable Fredholm module Categories:19k56, 46L87, , 58B34 

3. CJM Online first
 Glöckner, Helge

Completeness of infinitedimensional Lie groups in their left uniformity
We prove completeness for the main examples
of infinitedimensional Lie groups and some related topological
groups.
Consider a sequence
$G_1\subseteq G_2\subseteq\cdots$ of topological groups~$G_n$
such that~$G_n$ is a subgroup of $G_{n+1}$ and the latter induces
the given topology on~$G_n$,
for each $n\in\mathbb{N}$.
Let $G$ be the direct limit of the sequence in the category of
topological groups.
We show that $G$ induces the given topology on each~$G_n$ whenever
$\bigcup_{n\in \mathbb{N}}V_1V_2\cdots V_n$ is an identity neighbourhood
in~$G$
for all identity neighbourhoods $V_n\subseteq G_n$. If, moreover,
each $G_n$ is complete, then~$G$ is complete.
We also show that the weak direct product $\bigoplus_{j\in J}G_j$
is complete for
each family $(G_j)_{j\in J}$ of complete Lie groups~$G_j$.
As a consequence, every strict direct limit $G=\bigcup_{n\in
\mathbb{N}}G_n$ of finitedimensional
Lie groups is complete, as well as the diffeomorphism group
$\operatorname{Diff}_c(M)$
of a paracompact finitedimensional smooth manifold~$M$
and the test function group $C^k_c(M,H)$, for each $k\in\mathbb{N}_0\cup\{\infty\}$
and complete Lie group~$H$
modelled on a complete locally convex space.
Keywords:infinitedimensional Lie group, left uniform structure, completeness Categories:22E65, 22A05, 22E67, 46A13, 46M40, 58D05 

4. CJM 2016 (vol 68 pp. 841)
 Gupta, Sanjiv Kumar; Hare, Kathryn

Characterizing the Absolute Continuity of the Convolution of Orbital Measures in a Classical Lie Algebra
Let $\mathfrak{g}$ be a compact, simple Lie algebra of dimension
$d$. It is
a classical result that the convolution of any $d$ nontrivial,
$G$invariant,
orbital measures is absolutely continuous with respect to
Lebesgue measure on $\mathfrak{g}$ and the sum of any $d$ nontrivial
orbits
has nonempty interior. The number $d$ was later reduced to the
rank of the
Lie algebra (or rank $+1$ in the case of type $A_{n}$). More
recently, the
minimal integer $k=k(X)$ such that the $k$fold convolution of
the orbital
measure supported on the orbit generated by $X$ is an absolutely
continuous
measure was calculated for each $X\in \mathfrak{g}$.
In this paper $\mathfrak{g}$ is any of the classical, compact,
simple Lie
algebras. We characterize the tuples $(X_{1},\dots,X_{L})$, with
$X_{i}\in
\mathfrak{g},$ which have the property that the convolution of
the $L$orbital
measures supported on the orbits generated by the $X_{i}$ is
absolutely continuous and, equivalently, the sum of their orbits
has
nonempty interior. The characterization depends on the Lie type
of
$\mathfrak{g}$ and the structure of the annihilating roots of
the $X_{i}$.
Such a characterization was previously known only for type $A_{n}$.
Keywords:compact Lie algebra, orbital measure, absolutely continuous measure Categories:43A80, 17B45, 58C35 

5. CJM 2016 (vol 69 pp. 241)
 Adamus, Janusz; Seyedinejad, Hadi

Finite Determinacy and Stability of Flatness of Analytic Mappings
It is proved that flatness of an analytic mapping germ from a
complete intersection is determined by its sufficiently high
jet. As a consequence, one obtains finite determinacy of complete
intersections. It is also shown that flatness and openness are
stable under deformations.
Keywords:finite determinacy, stability, flatness, openness, complete intersection Categories:58K40, 58K25, 32S05, 58K20, 32S30, 32B99, 32C05, 13B40 

6. CJM 2014 (vol 67 pp. 107)
7. CJM 2012 (vol 65 pp. 879)
 Kawabe, Hiroko

A Space of Harmonic Maps from the Sphere into the Complex Projective Space
GuestOhnita and Crawford have shown the pathconnectedness of the
space of harmonic maps from $S^2$ to $\mathbf{C} P^n$
of a fixed degree and energy.It is wellknown that the $\partial$ transform is defined on this space.
In this paper,we will show that the space is decomposed into mutually disjoint connected subspaces on which
$\partial$ is homeomorphic.
Keywords:harmonic maps, harmonic sequences, gluing Categories:58E20, 58D15 

8. CJM 2012 (vol 65 pp. 1255)
 IglesiasZemmour, Patrick

Variations of Integrals in Diffeology
We establish the formula for the variation of
integrals of differential forms on cubic chains, in the
context of diffeological spaces. Then, we establish the diffeological version of Stoke's
theorem, and we apply that to get the diffeological variant of the
CartanLie formula. Still in the context of CartanDeRham calculus
in diffeology, we
construct a ChainHomotopy Operator $\mathbf K$ we apply it here to
get the homotopic invariance of De Rham cohomology for
diffeological spaces. This is the ChainHomotopy Operator which used in
symplectic diffeology to construct the Moment Map.
Keywords:diffeology, differential geometry, CartanDeRham calculus Categories:58A10, 58A12, 58A40 

9. CJM 2012 (vol 65 pp. 544)
 Deitmar, Anton; Horozov, Ivan

Iterated Integrals and Higher Order Invariants
We show that higher order invariants of smooth functions can be
written as linear combinations of full invariants times iterated
integrals.
The nonuniqueness of such a presentation is captured in the kernel of
the ensuing map from the tensor product. This kernel is computed
explicitly.
As a consequence, it turns out that higher order invariants are a free
module of the algebra of full invariants.
Keywords:higher order forms, iterated integrals Categories:14F35, 11F12, 55D35, 58A10 

10. CJM 2011 (vol 64 pp. 924)
 McCann, Robert J.; Pass, Brendan; Warren, Micah

Rectifiability of Optimal Transportation Plans
The regularity of solutions to optimal transportation problems has become
a hot topic in current research. It is well known by now that the optimal measure
may not be concentrated on the graph of a continuous mapping unless both the transportation
cost and the masses transported satisfy very restrictive hypotheses (including sign conditions
on the mixed fourthorder derivatives of the cost function).
The purpose of this note is to show that in spite of this,
the optimal measure is supported on a Lipschitz manifold, provided only
that the cost is $C^{2}$ with nonsingular mixed second derivative.
We use this result to provide a simple proof that solutions to Monge's
optimal transportation problem satisfy a change of variables equation
almost everywhere.
Categories:49K20, 49K60, 35J96, 58C07 

11. CJM 2011 (vol 63 pp. 721)
 Autin, Aymeric

Isoresonant Complexvalued Potentials and Symmetries
Let $X$ be a connected Riemannian manifold such that the resolvent of
the free Laplacian $(\Deltaz)^{1}$, $z\in\mathbb{C} \setminus
\mathbb{R}^+$, has a meromorphic continuation
through $\mathbb{R}^+$. The poles of this continuation are called
resonances. When $X$ has some symmetries, we construct complexvalued
potentials, $V$, such that the resolvent of $\Delta+V$, which has also
a meromorphic continuation, has the same resonances with
multiplicities as the free Laplacian.
Categories:31C12, 58J50 

12. CJM 2010 (vol 63 pp. 55)
 Chau, Albert; Tam, LuenFai; Yu, Chengjie

Pseudolocality for the Ricci Flow and Applications
Perelman established a differential LiYauHamilton
(LYH) type inequality for fundamental solutions of the conjugate
heat equation corresponding to the Ricci flow on compact manifolds.
As an application of the LYH inequality,
Perelman proved a pseudolocality result for the Ricci flow on
compact manifolds. In this article we provide the details for the
proofs of these results in the case of a complete noncompact
Riemannian manifold. Using these results we prove that under
certain conditions, a finite time singularity of the Ricci flow
must form within a compact set. The conditions are satisfied by
asymptotically flat manifolds. We also prove a long time existence
result for the K\"ahlerRicci flow on complete nonnegatively curved K\"ahler
manifolds.
Categories:53C44, 58J37, 35B35 

13. CJM 2010 (vol 62 pp. 1264)
 Chen, Jingyi; Fraser, Ailana

Holomorphic variations of minimal disks with boundary on a Lagrangian surface
Let $L$ be an oriented Lagrangian submanifold in an $n$dimensional
KÃ¤hler manifold~$M$. Let $u \colon D \to M$ be a minimal immersion
from a disk $D$ with $u(\partial D) \subset L$ such that $u(D)$ meets
$L$ orthogonally along $u(\partial D)$. Then the real dimension of
the space of admissible holomorphic variations is at least
$n+\mu(E,F)$, where $\mu(E,F)$ is a boundary Maslov index; the minimal
disk is holomorphic if there exist $n$ admissible holomorphic
variations that are linearly independent over $\mathbb{R}$ at some
point $p \in \partial D$; if $M = \mathbb{C}P^n$ and $u$ intersects
$L$ positively, then $u$ is holomorphic if it is stable, and its
Morse index is at least $n+\mu(E,F)$ if $u$ is unstable.
Categories:58E12, 53C21, 53C26 

14. CJM 2010 (vol 62 pp. 1325)
15. CJM 2009 (vol 62 pp. 52)
 Deng, Shaoqiang

An Algebraic Approach to Weakly Symmetric Finsler Spaces
In this paper, we introduce a new algebraic notion, weakly symmetric
Lie algebras, to give an algebraic description of an
interesting class of homogeneous RiemannFinsler spaces, weakly symmetric
Finsler spaces. Using this new definition, we are able to give a
classification of weakly symmetric Finsler spaces with dimensions $2$
and $3$. Finally, we show that all the nonRiemannian reversible weakly
symmetric Finsler spaces we find are nonBerwaldian and with vanishing
Scurvature. This means that reversible nonBerwaldian Finsler spaces
with vanishing Scurvature may exist at large. Hence the generalized
volume comparison theorems due to Z. Shen are valid for a rather large
class of Finsler spaces.
Keywords:weakly symmetric Finsler spaces, weakly symmetric Lie algebras, Berwald spaces, Scurvature Categories:53C60, 58B20, 22E46, 22E60 

16. CJM 2009 (vol 62 pp. 242)
17. CJM 2009 (vol 61 pp. 548)
 Girouard, Alexandre

Fundamental Tone, Concentration of Density, and Conformal Degeneration on Surfaces
We study the effect of two types of degeneration of a Riemannian
metric on the first eigenvalue of the Laplace operator on
surfaces. In both cases we prove that the first eigenvalue of the
round sphere is an optimal asymptotic upper bound. The first type of
degeneration is concentration of the density to a point within a
conformal class. The second is degeneration of the
conformal class to the boundary of the moduli space on the torus and
on the Klein bottle. In the latter, we follow the outline proposed
by N. Nadirashvili in 1996.
Categories:35P, 58J 

18. CJM 2008 (vol 60 pp. 1336)
 Olver, Peter J.; Pohjanpelto, Juha

Moving Frames for Lie PseudoGroups
We propose a new, constructive theory of moving frames for Lie
pseudogroup actions on submanifolds. The moving frame provides an
effective means for determining complete systems of differential
invariants and invariant differential forms, classifying their
syzygies and recurrence relations, and solving equivalence and
symmetry problems arising in a broad range of applications.
Categories:58A15, 58A20, 58H05, 58J70 

19. CJM 2008 (vol 60 pp. 1149)
 Petersen, Kathleen L.; Sinclair, Christopher D.

Conjugate Reciprocal Polynomials with All Roots on the Unit Circle
We study the geometry, topology and Lebesgue measure of the set of
monic conjugate reciprocal polynomials of fixed degree with all
roots on the unit circle. The set of such polynomials of degree $N$
is naturally associated to a subset of $\R^{N1}$. We calculate
the volume of this set, prove the set is homeomorphic to the $N1$
ball and that its isometry group is isomorphic to the dihedral
group of order $2N$.
Categories:11C08, 28A75, 15A52, 54H10, 58D19 

20. CJM 2008 (vol 60 pp. 822)
 Kuwae, Kazuhiro

Maximum Principles for Subharmonic Functions Via Local SemiDirichlet Forms
Maximum principles for subharmonic
functions in the framework of quasiregular local semiDirichlet
forms admitting lower bounds are presented.
As applications, we give
weak and strong maximum principles
for (local) subsolutions of a second order elliptic
differential operator on the domain of Euclidean space under conditions on coefficients,
which partially generalize the results by Stampacchia.
Keywords:positivity preserving form, semiDirichlet form, Dirichlet form, subharmonic functions, superharmonic functions, harmonic functions, weak maximum principle, strong maximum principle, irreducibility, absolute continuity condition Categories:31C25, 35B50, 60J45, 35J, 53C, 58 

21. CJM 2008 (vol 60 pp. 572)
 Hitrik, Michael; Sj{östrand, Johannes

NonSelfadjoint Perturbations of Selfadjoint Operators in Two Dimensions IIIa. One Branching Point
This is the third in a series of works devoted to spectral
asymptotics for nonselfadjoint
perturbations of selfadjoint $h$pseudodifferential operators in dimension 2, having a
periodic classical flow. Assuming that the strength $\epsilon$
of the perturbation is in the range $h^2\ll \epsilon \ll h^{1/2}$
(and may sometimes reach even smaller values), we
get an asymptotic description of the eigenvalues in rectangles
$[1/C,1/C]+i\epsilon [F_01/C,F_0+1/C]$, $C\gg 1$, when $\epsilon F_0$ is a saddle point
value of the flow average of the leading perturbation.
Keywords:nonselfadjoint, eigenvalue, periodic flow, branching singularity Categories:31C10, 35P20, 35Q40, 37J35, 37J45, 53D22, 58J40 

22. CJM 2008 (vol 60 pp. 241)
 Alexandrova, Ivana

SemiClassical Wavefront Set and Fourier Integral Operators
Here we define and prove some properties of the semiclassical
wavefront set. We also define and study semiclassical Fourier
integral operators and prove a generalization of Egorov's theorem to
manifolds of different dimensions.
Keywords:wavefront set, Fourier integral operators, Egorov theorem, semiclassical analysis Categories:35S30, 35A27, 58J40, 81Q20 

23. CJM 2008 (vol 60 pp. 457)
 Teplyaev, Alexander

Harmonic Coordinates on Fractals with Finitely Ramified Cell Structure
We define sets with finitely ramified cell structure, which are
generalizations of postcrit8cally finite selfsimilar
sets introduced by Kigami and of fractafolds introduced by Strichartz. In general,
we do not assume even local selfsimilarity, and allow countably many cells
connected at each junction point.
In particular, we consider postcritically infinite fractals.
We prove that if Kigami's resistance form
satisfies certain assumptions, then there exists a weak Riemannian metric
such that the energy can be expressed as the integral of the norm squared
of a weak gradient with respect to an energy measure.
Furthermore, we prove that if such a set can be homeomorphically represented
in harmonic coordinates, then for smooth functions the weak gradient can be
replaced by the usual gradient.
We also prove a simple formula for the energy measure Laplacian in harmonic
coordinates.
Keywords:fractals, selfsimilarity, energy, resistance, Dirichlet forms, diffusions, quantum graphs, generalized Riemannian metric Categories:28A80, 31C25, 53B99, 58J65, 60J60, 60G18 

24. CJM 2008 (vol 60 pp. 297)
 Bini, G.; Goulden, I. P.; Jackson, D. M.

Transitive Factorizations in the Hyperoctahedral Group
The classical Hurwitz enumeration problem has a presentation in terms of
transitive factorizations in the symmetric group. This presentation suggests
a generalization from type~$A$ to other
finite reflection groups and, in particular, to type~$B$.
We study this generalization both from a combinatorial and a geometric
point of view, with the prospect of providing a means of understanding more
of the structure of the moduli spaces of maps with an $\gS_2$symmetry.
The type~$A$ case has been well studied and connects Hurwitz numbers
to the moduli space of curves. We conjecture an analogous setting for the
type~$B$ case that is studied here.
Categories:05A15, 14H10, 58D29 

25. CJM 2007 (vol 59 pp. 1245)
 Chen, Qun; Zhou, ZhenRong

On Gap Properties and Instabilities of $p$YangMills Fields
We consider the
$p$YangMills functional
$(p\geq 2)$
defined as
$\YM_p(\nabla):=\frac 1 p \int_M \\rn\^p$.
We call critical points of $\YM_p(\cdot)$ the $p$YangMills
connections, and the associated curvature $\rn$ the $p$YangMills
fields. In this paper, we prove gap properties and instability theorems for $p$YangMills
fields over submanifolds in $\mathbb{R}^{n+k}$ and $\mathbb{S}^{n+k}$.
Keywords:$p$YangMills field, gap property, instability, submanifold Categories:58E15, 53C05 
