
Page 


3  Periodic steadystate solutions of a liquid film model via a classical method Alhasanat, Ahmad; Ou, Chunhua
In this paper, periodic steadystate of a liquid film flowing
over a periodic uneven wall is investigated via a classical method.
Specifically, we analyze a longwave model that is valid at
the nearcritical Reynolds number. For the periodic wall surface,
we construct an iteration scheme in terms of an integral form
of the original steadystate problem. The uniform convergence
of the scheme is proved so that we can derive the existence and
the uniqueness, as well as the asymptotic formula, of the periodic
solutions.


16  Classification of simple weight modules over the Schrödinger algebra Bavula, V. V.; Lu, T.
A classification of simple weight modules over the Schrödinger
algebra is given. The Krull and the global dimensions are found
for the centralizer $C_{\mathcal{S}}(H)$ (and some of its prime factor
algebras) of the Cartan element $H$ in the universal enveloping
algebra $\mathcal{S}$ of the Schrödinger (Lie) algebra. The simple
$C_{\mathcal{S}}(H)$modules are classified. The Krull and the global
dimensions are found for some (prime) factor algebras of the
algebra $\mathcal{S}$ (over the centre). It is proved that some (prime)
factor algebras of $\mathcal{S}$ and $C_{\mathcal{S}}(H)$ are tensor homological/Krull
minimal.


40  A sharp bound on RIC in generalized orthogonal matching pursuit Chen, Wengu; Ge, Huanmin
Generalized orthogonal matching pursuit (gOMP) algorithm has
received much attention in recent years as a natural extension
of
orthogonal matching pursuit (OMP). It is used to recover sparse
signals in compressive sensing. In this paper, a new bound is
obtained for the exact reconstruction of every $K$sparse signal
via
the gOMP algorithm in the noiseless case. That is, if the restricted
isometry constant (RIC) $\delta_{NK+1}$ of the sensing matrix
$A$
satisfies $ \delta_{NK+1}\lt \frac{1}{\sqrt{\frac{K}{N}+1}}$, then
the
gOMP can perfectly recover every $K$sparse signal $x$ from $y=Ax$.
Furthermore, the bound is proved to be sharp.
In the noisy case, the above bound on RIC combining with an
extra condition on the minimum
magnitude of the nonzero components of $K$sparse signals can
guarantee
that the gOMP selects all of support indices of the $K$sparse
signals.


55  Enumerating unlabelled embeddings of digraphs Chen, Yichao; Gao, Xiaojian; Huang, Yuanqiu
A $2$cell embedding of an Eulerian digraph $D$
into a closed surface is said to be directed if the
boundary of each face is a directed closed walk in $D$. In this
paper, a method is developed with the purpose of enumerating
unlabelled embeddings for an Eulerian digraph. As an application,
we obtain explicit formulas for the number of unlabelled embeddings
of directed bouquets of cycles $B_n$, directed dipoles $OD_{2n}$
and for a class of regular tournaments $T_{2n+1}$.


70  Hilbert Transformation and Representation of the $ax+b$ Group Dang, Pei; Liu, Hua; Qian, Tao
In this paper we study the Hilbert transformations over
$L^2(\mathbb{R})$
and $L^2(\mathbb{T})$ from
the viewpoint of symmetry. For a linear operator over $L^2(\mathbb{R})$
commutative with the ax+b group we show that the operator is
of the form
$
\lambda I+\eta H,
$
where $I$ and $H$ are the identity operator and Hilbert transformation
respectively, and $\lambda,\eta$ are complex numbers. In the
related literature this result was proved through first invoking
the boundedness result of the operator, proved though a big
machinery.
In our setting the boundedness is a consequence of the boundedness
of the Hilbert transformation. The methodology that we use is
GelfandNaimark's representation of the ax+b group. Furthermore
we prove a similar result on the unit circle. Although there
does not exist a group like ax+b on the unit circle, we construct
a semigroup to play the same symmetry role for the Hilbert transformations
over the circle $L^2(\mathbb{T}).$


85  On subcritically Stein fillable 5manifolds Ding, Fan; Geiges, Hansjörg; Zhang, Guangjian
We make some elementary observations concerning subcritically
Stein
fillable contact structures on $5$manifolds.
Specifically, we determine the diffeomorphism type of such
contact manifolds in the case the fundamental group is finite
cyclic,
and we show that on the $5$sphere the standard contact structure
is the unique subcritically fillable one. More generally,
it is shown that subcritically fillable contact structures
on simply connected $5$manifolds are determined by their
underlying almost contact structure. Along the way, we discuss
the
homotopy classification of almost contact structures.


97  On a singular integral of ChristJourné type with homogeneous kernel Ding, Yong; Lai, Xudong
In this paper, we prove that the following singular integral
defined by
$$T_{\Omega,a}f(x)=\operatorname{p.v.}\int_{\mathbb{R}^{d}}\frac{\Omega(xy)}{xy^d}\cdot m_{x,y}a\cdot
f(y)dy$$
is bounded on $L^p(\mathbb{R}^d)$ for $1\lt p\lt \infty$ and is of weak type
(1,1), where $\Omega\in L\log^+L(\mathbb{S}^{d1})$ and
$m_{x,y}a=:\int_0^1a(sx+(1s)y)ds$
with $a\in L^\infty(\mathbb{R}^d)$ satisfying some restricted conditions.


114  A characterization of $C^{\ast}$normed algebras via positive functionals Haralampidou, Marina; Oudadess, Mohamed; Palacios, Lourdes; Signoret, Carlos
We give a characterization of $C^{\ast}$normed algebras, among
certain involutive normed ones. This is done through the existence
of enough specific positive functionals. The same question is
also
examined in some non normed (topological) algebras.


124  The Jordan Curve Theorem via Complex Analysis Hemasundar, Gollakota V. V.; Simha, R. R.
The aim of this article is to give a proof of the Jordan Curve
Theorem via complex analysis.


130  Additive maps on units of rings Koşan, Tamer; Sahinkaya, Serap; Zhou, Yiqiang
Let $R$ be a ring. A map $f: R\rightarrow R$
is additive if $f(a+b)=f(a)+f(b)$ for all elements $a$ and $b$
of $R$.
Here a map $f: R\rightarrow R$ is called unitadditive if $f(u+v)=f(u)+f(v)$
for all units $u$ and $v$ of $R$. Motivated by a recent result
of Xu, Pei and Yi
showing that, for any field $F$, every
unitadditive map of ${\mathbb M}_n(F)$ is additive for all $n\ge
2$, this paper is about the question when every unitadditive
map of a ring is additive. It is proved that every unitadditive
map of a semilocal ring $R$ is additive if and only if either
$R$ has no homomorphic image isomorphic to $\mathbb Z_2$ or $R/J(R)\cong
\mathbb Z_2$ with $2=0$ in $R$. Consequently, for any semilocal
ring $R$, every unitadditive map of ${\mathbb M}_n(R)$ is additive
for all $n\ge 2$. These results are further extended to rings
$R$ such that $R/J(R)$ is a direct product of exchange rings
with primitive factors Artinian. A unitadditive map $f$ of a
ring $R$ is called unithomomorphic if $f(uv)=f(u)f(v)$ for all
units $u,v$ of $R$. As an application, the question of when every
unithomomorphic map of a ring is an endomorphism is addressed.


142  An Equivalent Form of Picard's Theorem and Beyond Li, Bao Qin
This paper gives an equivalent form of Picard's
theorem via entire solutions of the functional equation $f^2+g^2=1$,
and then its improvements and applications to certain nonlinear
(ordinary and partial) differential equations.


149  Global phase portraits for the Abel quadratic polynomial differential equations of second kind with $Z_2$symmetries Llibre, Jaume; Valls, Claudia
We provide normal forms and the global phase portraits on the
Poincaré disk for all Abel quadratic polynomial differential
equations of the second kind with $\mathbb Z_2$symmetries.


166  A moduletheoretic characterization of algebraic hypersurfaces MirandaNeto, Cleto B.
In this note we prove the following surprising characterization:
if
$X\subset {\mathbb A}^n$ is an (embedded, nonempty, proper)
algebraic variety defined over a
field $k$ of characteristic zero, then $X$ is a hypersurface
if and only if the module $T_{{\mathcal O}_{{\mathbb
A}^n}/k}(X)$ of logarithmic vector fields of
$X$ is a reflexive ${\mathcal
O}_{{\mathbb A}^n}$module. As a consequence of this result,
we derive that if $T_{{\mathcal O}_{{\mathbb A}^n}/k}(X)$ is a
free ${\mathcal
O}_{{\mathbb A}^n}$module, which is shown to be equivalent
to the freeness of the $t$th exterior power of $T_{{\mathcal O}_{{\mathbb
A}^n}/k}(X)$ for some (in fact, any) $t\leq n$, then necessarily
$X$ is a Saito free divisor.


174  A factorization result for classical and similitude groups Roche, Alan; Vinroot, C. Ryan
For most classical and similitude groups, we show that each element
can be written as a product of two transformations that
a) preserve or almost preserve the underlying form and b) whose
squares are certain scalar maps. This generalizes work of Wonenburger
and Vinroot.
As an application, we reprove and slightly extend a well known
result of Mœglin, Vignéras and Waldspurger on the existence
of automorphisms of $p$adic classical groups that take each
irreducible smooth representation to its dual.


191  The FeffermanStein type inequalities for strong and directional maximal operators in the plane Saito, Hiroki; Tanaka, Hitoshi
The FeffermanStein type inequalities
for strong maximal operator and directional maximal operator
are verified with an additional composition of the HardyLittlewood
maximal operator in the plane.


201  Projective plane bundles over an elliptic curve Takahashi, Tomokuni
We calculate the dimension of cohomology groups for
the holomorphic tangent bundles of each isomorphism
class of the projective plane bundle over an elliptic curve.
As an application, we construct the families
of projective plane bundles, and prove that the families
are effectively parametrized and complete.


211  The asymptotics of the higher dimensional Reidemeister torsion for exceptional surgeries along twist knots Tran, Anh T.; Yamaguchi, Yoshikazu
We determine the asymptotic behavior of the higher dimensional
Reidemeister torsion for
the graph manifolds obtained by exceptional surgeries along
twist knots.
We show that all irreducible
$\operatorname{SL}_2(\mathbb{C})$representations of the graph
manifold
are induced by irreducible metabelian representations of the
twist knot group.
We also give the set of the limits of the leading coefficients
in the higher dimensional Reidemeister torsion explicitly.


225  Higher $\ell^2$Betti Numbers of Universal Quantum Groups Bichon, Julien; Kyed, David; Raum, Sven
We calculate all $\ell^2$Betti numbers of the universal discrete
Kac quantum groups $\hat{\mathrm U}^+_n$ as well as their halfliberated
counterparts $\hat{\mathrm U}^*_n$.


236  A Note on Uniformly Bounded Cocycles into Finite von Neumann Algebras Boutonnet, Remi; Roydor, Jean
We give a short proof of a result of T. Bates
and T. Giordano stating that any uniformly bounded Borel cocycle
into a finite von Neumann algebra is cohomologous to a unitary
cocycle. We also point out a separability issue in
their proof. Our approach is based on the existence of a nonpositive
curvature metric on the positive cone of a finite von Neumann
algebra.


240  Hölder Continuous Solutions of Degenerate Differential Equations with Finite Delay Bu, Shangquan; Cai, Gang
Using known operatorvalued Fourier multiplier results on vectorvalued
Hölder continuous function spaces $C^\alpha (\mathbb R; X)$, we completely
characterize the $C^\alpha$wellposedness of the first order
degenerate differential equations with finite delay $(Mu)'(t)
= Au(t) + Fu_t + f(t)$ for $t\in\mathbb R$
by the boundedness of the $(M, F)$resolvent of $A$ under suitable
assumption on the delay operator $F$, where $A, M$ are closed
linear
operators on a Banach space $X$ satisfying $D(A)\cap D(M) \not=\{0\}$,
the delay operator $F$ is a bounded linear operator
from $C([r, 0]; X)$ to $X$ and $r \gt 0$ is fixed.


252  Connectivity in Hypergraphs Dewar, Megan; Pike, David; Proos, John
In this paper we consider two natural notions of connectivity
for hypergraphs: weak and strong. We prove that the strong
vertex connectivity of a connected hypergraph is bounded by its
weak edge connectivity, thereby extending a theorem of Whitney
from graphs to hypergraphs. We find that while determining a
minimum weak vertex cut can be done in polynomial time and is
equivalent to finding a minimum vertex cut in the 2section of
the hypergraph in question, determining a minimum strong vertex
cut is NPhard for general hypergraphs. Moreover, the problem
of finding minimum strong vertex cuts remains NPhard when restricted
to hypergraphs with maximum edge size at most 3. We also discuss
the relationship between strong vertex connectivity and the
minimum
transversal problem for hypergraphs, showing that there are
classes
of hypergraphs for which one of the problems is NPhard while
the other can be solved in polynomial time.


272  Symmetric Products of Equivariantly Formal Spaces Franz, Matthias
Let \(X\) be a CW complex with a continuous action of a topological
group \(G\).
We show that if \(X\) is equivariantly formal for singular
cohomology
with coefficients in some field \(\Bbbk\), then so are all symmetric
products of \(X\)
and in fact all its \(\Gamma\)products.
In particular, symmetric products
of quasiprojective Mvarieties are again Mvarieties.
This generalizes a result by Biswas and D'Mello
about symmetric products of Mcurves.
We also discuss several related questions.


282  The Initial and Terminal Cluster Sets of an Analytic Curve Gauthier, Paul M
For an analytic curve $\gamma:(a,b)\rightarrow \mathbb C,$ the set of
values approached by $\gamma(t),$ as $t\searrow a$ and as $t\nearrow
b$ can be any two continuua of $\mathbb C\cup\{\infty\}.$


289  A Realanalytic Nonpolynomially Convex Isotropic Torus with No Attached Discs Gupta, Purvi
We show by means of an example in $\mathbb C^3$ that Gromov's
theorem on the presence of attached holomorphic discs for compact
Lagrangian manifolds is not true in the subcritical
realanalytic case, even in the absence of an obvious obstruction,
i.e, polynomial convexity.


292  A Note on a Unicity Theorem for the Gauss Maps of Complete Minimal Surfaces in Euclidean Fourspace Ha, Pham Hoang; Kawakami, Yu
The classical result of Nevanlinna states that two nonconstant
meromorphic functions on the complex plane having the
same images for five distinct values must be identically equal
to each other. In this paper, we give a similar uniqueness theorem for the Gauss maps of complete minimal surfaces in Euclidean
fourspace.


301  Remarks on Hopf Images and Quantum Permutation Groups $S_n^+$ Józiak, Paweł
Motivated by a question of A. Skalski and P.M. Sołtan (2016)
about inner faithfulness of the S. Curran's map of extending
a quantum increasing sequence to a quantum permutation, we revisit
the results and techniques of T. Banica and J. Bichon (2009)
and study some grouptheoretic properties of the quantum permutation
group on $4$ points. This enables us not only to answer the aforementioned
question in positive in case $n=4, k=2$, but also to classify
the automorphisms of $S_4^+$, describe all the embeddings $O_{1}(2)\subset
S_4^+$ and show that all the copies of $O_{1}(2)$ inside $S_4^+$
are conjugate. We then use these results to show that the converse
to the criterion we applied to answer the aforementioned question
is not valid.


318  Adnilpotent Elements of Semiprime Rings with Involution Lee, TsiuKwen
Let $R$ be an $n!$torsion free semiprime ring with
involution $*$ and with extended centroid $C$, where $n\gt 1$ is
a positive integer. We characterize $a\in K$, the Lie algebra
of skew elements in $R$, satisfying $(\operatorname{ad}_a)^n=0$ on $K$. This
generalizes both Martindale and Miers' theorem
and the theorem of Brox et al.
To prove it we
first prove that if $a, b\in R$ satisfy
$(\operatorname{ad}_a)^n=\operatorname{ad}_b$ on
$R$, where either $n$ is even or $b=0$, then
$\big(a\lambda\big)^{[\frac{n+1}{2}]}=0$
for some $\lambda\in C$.


328  Moduli of Space Sheaves with Hilbert Polynomial $4m+1$ Maican, Mario
We investigate the moduli space of sheaves supported on space
curves of degree $4$ and having Euler characteristic $1$.
We give an elementary proof of the fact that this moduli space
consists of three irreducible components.


346  Counting Separable Polynomials in $\mathbb{Z}/n[x]$ Polak, Jason K. C.
For a commutative ring $R$, a polynomial $f\in R[x]$ is called
separable if $R[x]/f$ is a separable $R$algebra. We derive formulae
for the number of separable polynomials when $R = \mathbb{Z}/n$, extending
a result of L. Carlitz. For instance, we show that the number
of separable polynomials in $\mathbb{Z}/n[x]$
that are separable is $\phi(n)n^d\prod_i(1p_i^{d})$
where $n = \prod p_i^{k_i}$ is the prime factorisation of $n$
and $\phi$ is Euler's totient function.


353  Ground State and Multiple Solutions for Kirchhoff Type Equations with Critical Exponent Qin, Dongdong; He, Yubo; Tang, Xianhua
In this paper, we consider the following
critical Kirchhoff type equation:
\begin{align*}
\left\{
\begin{array}{lll}

\left(a+b\int_{\Omega}\nabla u^2
\right)\Delta u=Q(x)u^4u + \lambda u^{q1}u,~~\mbox{in}~~\Omega,
\\
u=0,\quad \text{on}\quad \partial \Omega,
\end{array}
\right.
\end{align*}
By using variational methods that are constrained to the Nehari
manifold,
we prove that the above equation has a ground state solution
for the case when $3\lt q\lt 5$.
The relation between the number of maxima of $Q$
and the number of positive solutions for the problem is also
investigated.


370  A Remark on Certain Integral Operators of Fractional Type Rocha, Pablo Alejandro
For $m, n \in \mathbb{N}$, $1\lt m \leq n$, we write $n = n_1 +
\dots + n_m$ where $\{ n_1, \dots, n_m \} \subset \mathbb{N}$. Let
$A_1, \dots, A_m$ be $n \times n$ singular real matrices such that
$\bigoplus_{i=1}^{m} \bigcap_{1\leq j \neq i \leq m} \mathcal{N}_j
= \mathbb{R}^{n},$ where
$\mathcal{N}_j = \{ x : A_j x = 0 \}$, $dim(\mathcal{N}_j)=nn_j$
and $A_1+ \dots+ A_m$ is invertible. In this paper we study integral
operators of the form
$T_{r}f(x)= \int_{\mathbb{R}^{n}} \, xA_1 y^{n_1 + \alpha_1}
\cdots xA_m y^{n_m + \alpha_m} f(y) \, dy,$
$n_1 + \dots + n_m = n$, $\frac{\alpha_1}{n_1} = \dots = \frac{\alpha_m}{n_m}=r$,
$0 \lt r \lt 1$, and the matrices $A_i$'s are as above. We obtain
the $H^{p}(\mathbb{R}^{n})L^{q}(\mathbb{R}^{n})$ boundedness
of $T_r$ for $0\lt p\lt \frac{1}{r}$ and $\frac{1}{q}=\frac{1}{p} 
r$.


376  Elliptic Zeta Functions and Equivariant Functions Sebbar, Abdellah; AlShbeil, Isra
In this paper we establish a close connection between three
notions attached to a modular subgroup. Namely the set of weight
two meromorphic modular forms, the set of equivariant functions
on the upper halfplane commuting with the action of the modular
subgroup and the set of elliptic zeta functions generalizing
the Weierstrass zeta functions. In particular, we show that the
equivariant functions can be parameterized by modular objects
as well as by elliptic objects.


390  A Multiplier Theorem on Anisotropic Hardy Spaces Wang, Lian Daniel
We present a multiplier theorem on anisotropic
Hardy spaces. When $m$ satisfies the anisotropic, pointwise Mihlin
condition, we obtain boundedness of the multiplier operator $T_m
: H_A^p (\mathbb R^n) \rightarrow H_A^p (\mathbb R^n)$, for the range of $p$
that depends on the eccentricities of the dilation $A$ and the
level of regularity of a multiplier symbol $m$. This extends
the classical multiplier theorem of Taibleson and Weiss.


405  Growth Rates of 3dimensional Hyperbolic Coxeter Groups are Perron Numbers Yukita, Tomoshige
In this paper we consider the growth rates of 3dimensional hyperbolic
Coxeter polyhedra with at least one dihedral angle of the form
$\frac{\pi}{k}$ for an integer $k\geq{7}$.
Combining a classical result by Parry with
a previous result of ours,
we prove that the growth rates of
3dimensional hyperbolic Coxeter groups are Perron numbers.


423  Stability of Traveling Wavefronts for a TwoComponent Lattice Dynamical System Arising in Competition Models Zhang, GuoBao; Tian, Ge
In this paper, we study a twocomponent LotkaVolterra competition
system
on an onedimensional spatial lattice. By the method of the comparison
principle together with
the weighted energy, we prove that the traveling wavefronts with
large speed are exponentially asymptotically stable,
when the initial perturbation around the traveling wavefronts
decays
exponentially as $j+ct \rightarrow \infty$, where $j\in\mathbb{Z}$,
$t\gt 0$, but the initial perturbation
can be arbitrarily large on other locations. This partially answers
an open problem by J.S. Guo and C.H. Wu.


438  Classification of Solutions for Harmonic Functions with Neumann Boundary Value Zhang, Tao; Zhou, Chunqin
In this paper, we classify all solutions of
\[
\left\{
\begin{array}{rcll}
\Delta u &=& 0 \quad &\text{ in }\mathbb{R}^{2}_{+},
\\
\dfrac{\partial u}{\partial t}&=&cx^{\beta}e^{u} \quad
&\text{ on }\partial \mathbb{R}^{2}_{+} \backslash \{0\},
\\
\end{array}
\right.
\]
with the finite conditions
\[
\int_{\partial \mathbb{R}^{2}_{+}}x^{\beta}e^{u}ds \lt C,
\qquad
\sup\limits_{\overline{\mathbb{R}^{2}_{+}}}{u(x)}\lt C.
\]
Here, $c$ is a positive number and $\beta \gt 1$.


449  Strongly extreme points and approximation properties Abrahamsen, Trond A.; Hájek, Petr; Nygaard, Olav; Troyanski, Stanimir L.
We show that if $x$ is a strongly extreme point of a bounded closed
convex subset of a Banach space and the identity has a geometrically
and topologically good enough local approximation at $x$, then $x$
is already a denting point. It turns out that such an approximation
of the identity exists at any strongly extreme point of the unit
ball of a Banach space with the unconditional compact approximation
property. We also prove that every Banach space with a Schauder
basis can be equivalently renormed to satisfy the sufficient
conditions mentioned.


458  Global holomorphic functions in several noncommuting variables II Agler, Jim; McCarthy, John
We give a new proof that bounded noncommutative functions
on polynomial polyhedra
can be represented by a realization formula, a generalization
of the transfer function realization
formula for bounded analytic functions on the unit disk.


464  A short proof of the characterization of model sets by almost automorphy Aujogue, JeanBaptiste
The aim of this note is to provide a conceptually simple demonstration
of the fact that repetitive model sets are characterized as the
repetitive Meyer sets with an almost automorphic associated dynamical
system.


473  A spectral identity on Jacobi polynomials and its analytic implications Awonusika, Richard; Taheri, Ali
The Jacobi coefficients $c^{\ell}_{j}(\alpha,\beta)$ ($1\leq
j\leq \ell$, $\alpha,\beta\gt 1$) are linked to the Maclaurin
spectral expansion of the Schwartz kernel of functions of the
Laplacian on a compact rank one symmetric space. It
is proved that these coefficients can be computed by transforming
the even derivatives of the the Jacobi polynomials $P_{k}^{(\alpha,\beta)}$ ($k\geq 0, \alpha,\beta\gt 1$) into a spectral sum associated with
the Jacobi operator. The first few coefficients are explicitly
computed and a direct trace
interpretation of the Maclaurin coefficients is presented.


483  Tannakian duality for affine homogeneous spaces Banica, Teodor
Associated to any closed quantum subgroup $G\subset U_N^+$ and
any index set $I\subset\{1,\dots,N\}$ is a certain homogeneous
space $X_{G,I}\subset S^{N1}_{\mathbb C,+}$, called affine homogeneous
space. We discuss here the abstract axiomatization of the algebraic
manifolds $X\subset S^{N1}_{\mathbb C,+}$ which can appear in
this way, by using Tannakian duality methods.


495  Poincaré Lemma on QuaternionLike Heisenberg Groups Chang, DerChen; Yang, Nanping; Wu, HsiChun
For smooth functions $a_1, a_2, a_3, a_4$ on a quaternion Heisenberg
group, we characterize
the existence of solutions of the partial differential operator
system $X_1f=a_1, X_2f=a_2, X_3f=a_3,$ and $X_4f=a_4$.
In addition, a formula for the solution function $f$ is deduced
provided the solvability of the system.


509  Area Integral Means of Analytic Functions in the Unit Disk Cui, Xiaohui; Wang, Chunjie; Zhu, Kehe
For an analytic function $f$ on the unit disk $\mathbb D$ we show that
the $L^2$ integral mean of $f$ on $c\lt z\lt r$ with
respect to the weighted area measure $(1z^2)^\alpha\,dA(z)$
is a logarithmically convex function of $r$ on $(c,1)$,
where $3\le\alpha\le0$ and $c\in[0,1)$. Moreover, the range
$[3,0]$ for $\alpha$ is best possible. When
$c=0$, our arguments here also simplify the proof for several
results we obtained in earlier papers.


518  Bounds on multiple selfavoiding polygons Hong, Kyungpyo; Oh, Seungsang
A selfavoiding polygon is a lattice polygon consisting of a
closed selfavoiding walk on a square lattice.
Surprisingly little is known rigorously about the enumeration
of selfavoiding polygons,
although there are numerous conjectures that are believed to
be true
and strongly supported by numerical simulations.
As an analogous problem of this study,
we consider multiple selfavoiding polygons in a confined region, as a model for multiple ring polymers in physics.
We find rigorous lower and upper bounds of the number $p_{m \times
n}$
of distinct multiple selfavoiding polygons in the $m \times
n$ rectangular grid on the square lattice.
For $m=2$, $p_{2 \times n} = 2^{n1}1$.
And, for integers $m,n \geq 3$,
$$2^{m+n3}
\left(\tfrac{17}{10}
\right)^{(m2)(n2)} \ \leq \ p_{m \times n} \ \leq \
2^{m+n3}
\left(\tfrac{31}{16}
\right)^{(m2)(n2)}.$$


531  $p$adic uniformization and the action of Galois on certain affine correspondences Ingram, Patrick
Given two monic polynomials $f$ and $g$ with coefficients in
a number field $K$, and some $\alpha\in K$, we examine the action
of the absolute Galois group $\operatorname{Gal}(\overline{K}/K)$ on the directed
graph of iterated preimages of $\alpha$ under the correspondence
$g(y)=f(x)$, assuming that $\deg(f)\gt \deg(g)$ and that $\gcd(\deg(f),
\deg(g))=1$. If a prime of $K$ exists at which $f$ and $g$ have
integral coefficients, and at which $\alpha$ is not integral,
we show that this directed graph of preimages consists of finitely
many $\operatorname{Gal}(\overline{K}/K)$orbits. We obtain this result by
establishing a $p$adic uniformization of such correspondences,
tenuously related to Böttcher's uniformization of polynomial
dynamical systems over $\mathbb{CC}$, although the construction of a
Böttcher coordinate for complex holomorphic correspondences
remains unresolved.


543  Lie derivatives and Ricci tensor on real hypersurfaces in complex twoplane Grassmannians Jeong, Imsoon; de Dios Pérez, Juan; Suh, Young Jin; Woo, Changhwa
On a real hypersurface $M$ in a complex twoplane Grassmannian
$G_2({\mathbb C}^{m+2})$ we have the Lie derivation ${\mathcal
L}$ and a differential operator of order one associated to the
generalized TanakaWebster connection $\widehat {\mathcal L}
^{(k)}$. We give a classification of real hypersurfaces $M$ on
$G_2({\mathbb C}^{m+2})$ satisfying
$\widehat {\mathcal L} ^{(k)}_{\xi}S={\mathcal L}_{\xi}S$, where
$\xi$ is the Reeb vector field on $M$ and $S$ the Ricci tensor
of $M$.


553  Branching Rules for $n$fold Covering Groups of $\mathrm{SL}_2$ over a NonArchimedean Local Field Karimianpour, Camelia
Let $\mathtt{G}$ be the $n$fold covering group of the special
linear group of degree two, over a nonArchimedean local field.
We determine the decomposition into irreducibles of the restriction
of the principal series representations of $\mathtt{G}$ to a maximal
compact subgroup. Moreover, we analyse those features that distinguish
this decomposition from the linear case.


572  Normalization of closed EkedahlOort strata Koskivirta, JeanStefan
We apply our theory of partial flag spaces developed
with W. Goldring
to study a grouptheoretical generalization of the canonical
filtration of a truncated BarsottiTate group of level 1. As
an application, we determine explicitly the normalization of
the Zariski closures of EkedahlOort strata of Shimura varieties
of Hodgetype as certain closed coarse strata in the associated
partial flag spaces.


588  $\mathsf{VB}$Courant algebroids, $\mathsf{E}$Courant algebroids and generalized geometry Lang, Honglei; Sheng, Yunhe; Wade, Aissa
In this paper, we first discuss the relation between $\mathsf{VB}$Courant
algebroids and $\mathsf{E}$Courant algebroids and construct some examples
of $\mathsf{E}$Courant algebroids. Then we introduce the notion of
a generalized complex
structure on an $\mathsf{E}$Courant algebroid, unifying the usual
generalized complex structures on evendimensional manifolds
and
generalized contact structures on odddimensional manifolds.
Moreover, we study generalized complex structures on an omniLie
algebroid in detail. In particular, we show that generalized
complex structures on an omniLie algebra $\operatorname{gl}(V)\oplus V$
correspond
to complex Lie algebra structures on $V$.


608  A note on $p$adic RankinSelberg $L$functions Loeffler, David
We prove an interpolation formula for the values of certain
$p$adic RankinSelberg $L$functions associated to nonordinary
modular forms.


622  On the size of an expression in the NymanBeurlingBáezDuarte criterion for the Riemann Hypothesis Maier, Helmut; Rassias, Michael Th.
A crucial role in the NymanBeurlingBáezDuarte approach to
the Riemann Hypothesis is played by the distance
\[
d_N^2:=\inf_{A_N}\frac{1}{2\pi}\int_{\infty}^\infty
\left1\zeta A_N
\left(\frac{1}{2}+it
\right)
\right^2\frac{dt}{\frac{1}{4}+t^2}\:,
\]
where the infimum is over all Dirichlet polynomials
$$A_N(s)=\sum_{n=1}^{N}\frac{a_n}{n^s}$$
of length $N$.
In this paper we investigate $d_N^2$ under the assumption that
the Riemann zeta function has four nontrivial zeros off the
critical line.


628  Differentialfree characterisation of smooth mappings with controlled growth Marković, Marijan
In this paper we give some generalizations and
improvements of the Pavlović result on the
HollandWalsh type characterization of the Bloch space of
continuously differentiable (smooth) functions in
the unit ball in $\mathbf{R}^m$.


637  Uniformization and Steinness Nemirovski, Stefan; Shafikov, Rasul Gazimovich
It is shown that the unit ball in $\mathbb{C}^n$ is the only complex manifold
that can universally cover both Stein and nonStein strictly pseudoconvex domains.


640  Remark on integral means of derivatives of Blaschke products Reijonen, Atte
If $B$ is the Blachke product with zeros $\{z_n\}$, then $B'(z)\le
\Psi_B(z)$, where
$$\Psi_B(z)=\sum_n \frac{1z_n^2}{1\overline{z}_nz^2}.$$
Moreover, it is a wellknown fact that, for $0\lt p\lt \infty$,
$$M_p(r,B')=
\left(\frac{1}{2\pi}\int_{0}^{2\pi} B'(re^{i\t})^p\,d\t
\right)^{1/p}, \quad 0\le r\lt 1,$$
is bounded if and only if $M_p(r,\Psi_B)$ is bounded.
We find a Blaschke product $B_0$ such that $M_p(r,B_0')$ and
$M_p(r,\Psi_{B_0})$ are not comparable for any $\frac12\lt p\lt \infty$.
In addition, it is shown that, if $0\lt p\lt \infty$, $B$ is a CarlesonNewman
Blaschke product and a weight $\omega$ satisfies a certain regularity
condition, then
$$
\int_\mathbb{D} B'(z)^p\omega(z)\,dA(z)\asymp \int_\mathbb{D} \Psi_B(z)^p\omega(z)\,dA(z),
$$
where $dA(z)$ is the Lebesgue area measure on the unit disc.


650  Connected numbers and the embedded topology of plane curves Shirane, Taketo
The splitting number of a plane irreducible curve for a Galois
cover is effective to distinguish the embedded topology of plane
curves.
In this paper, we define the connected number of a plane
curve (possibly reducible) for a Galois cover, which is similar
to the splitting number.
By using the connected number, we distinguish the embedded topology
of Artal arrangements of degree $b\geq 4$, where an Artal arrangement
of degree $b$ is a plane curve consisting of one smooth curve
of degree $b$ and three of its total inflectional tangen


659  On Deformations of Nodal Hypersurfaces Wang, Zhenjian
We extend the infinitesimal Torelli theorem for smooth hypersurfaces
to nodal hypersurfaces.


673  Relative Equilibria in Curved Restricted $4$body Problems Alhowaity, Sawsan; Diacu, Florin; PérezChavela, Ernesto
We consider the curved $4$body problems on spheres and hyperbolic
spheres. After obtaining a criterion for the existence of quadrilateral
configurations on the equator of the sphere, we study two restricted
$4$body problems, one in which two masses are negligible, and
another in which only one mass is negligible.
In the former we prove the evidence squarelike relative equilibria,
whereas in the latter we discuss the existence of kiteshaped
relative equilibria.


688  The Universal Enveloping Algebra of the Schrödinger Algebra and its Prime Spectrum Bavula, V. V.; Lu, T.
The prime, completely prime, maximal and primitive spectra are
classified for the universal enveloping algebra of the Schrödinger
algebra. For all of these ideals their explicit generators are
given. A counterexample is constructed to the conjecture of Cheng
and Zhang about nonexistence of simple singular Whittaker modules
for the Schrödinger algebra (and all such modules are classified).
It is proved that the conjecture holds 'generically'.


704  Remarks on Inner Functions and Optimal Approximants Bénéteau, Catherine Anne; Fleeman, Matthew C.; Khavinson, Dmitry S.; Seco, Daniel; Sola, Alan
We discuss the concept of inner function in reproducing kernel Hilbert spaces with an orthogonal basis of monomials and examine connections between inner functions and optimal polynomial approximants to $1/f$, where $f$ is a function in the space. We revisit some classical examples from this perspective, and show how a construction of Shapiro and Shields can be modified to produce inner functions.


717  Periodic Solutions of Second Order Degenerate Differential Equations with Delay in Banach Spaces Bu, Shangquan; Cai, Gang
We give necessary and sufficient
conditions of the $L^p$wellposedness (resp. $B_{p,q}^s$wellposedness) for the second order degenerate
differential equation with finite delays:
$(Mu)''(t)+Bu'(t)+Au(t)=Gu'_t+Fu_t+f(t),(t\in [0,2\pi])$ with periodic
boundary conditions $(Mu)(0)=(Mu)(2\pi)$, $(Mu)'(0)=(Mu)'(2\pi)$, where
$A, B, M$ are closed linear operators on a complex Banach space $X$ satisfying
$D(A)\cap D(B)\subset D(M)$, $F$ and $G$ are bounded linear operators from
$L^p([2\pi,0];X)$ (resp. $B_{p,q}^s([2\pi,0];X)$) into $X$.


738  Poincaré Inequalities and Neumann Problems for the $p$Laplacian CruzUribe, David; Rodney, Scott; Rosta, Emily
We prove an equivalence between weighted Poincaré inequalities
and
the existence of weak solutions to a Neumann problem related
to a
degenerate $p$Laplacian. The Poincaré inequalities are
formulated in the context of degenerate Sobolev spaces defined
in
terms of a quadratic form, and the associated matrix is the
source of
the degeneracy in the $p$Laplacian.


754  A Note on Concordance Properties of Fibers in Seifert Homology Spheres Lidman, Tye; Tweedy, Eamonn
In this note, we collect various properties
of Seifert homology spheres from the viewpoint of Dehn surgery
along a Seifert fiber. We expect that many of these are known
to various experts, but include them in one place which we hope
to be useful in the study of concordance and homology cobordism.


768  Chaotic Vibration of a Twodimensional Nonstrictly Hyperbolic Equation Li, Liangliang; Tian, Jing; Chen, Goong
The study of chaotic vibration for multidimensional PDEs due
to nonlinear boundary conditions is challenging. In this paper,
we mainly investigate the chaotic oscillation of a twodimensional
nonstrictly hyperbolic equation due to an energyinjecting
boundary condition and a distributed selfregulating boundary
condition. By using the method of characteristics, we give a
rigorous proof of the onset of the chaotic vibration phenomenon
of the 2D nonstrictly hyperbolic equation. We have also found
a regime of the parameters when the chaotic vibration phenomenon
occurs. Numerical simulations are also provided.


787  Endpoint Estimates of Riesz Transforms Associated with Generalized Schrödinger Operators Liu, Yu; Qi, Shuai
In this paper we establish the endpoint estimates
and Hardy type estimates for the Riesz transform associated
with the generalized Schrödinger operator.


802  The Oscillatory HyperHilbert Transform Associated with Plane Curves Li, Junfeng; Yu, Haixia
In this paper, the bounded properties of oscillatory hyperHilbert
transform along certain plane curves $\gamma(t)$
$$T_{\alpha,\beta}f(x,y)=\int_{0}^1f(xt,y\gamma(t))e^{ i t^{\beta}}\frac{\textrm{d}t}{t^{1+\alpha}}$$
were studied. For a general curves, these operators are bounded
in ${L^2(\mathbb{R}^{2})}$, if $\beta\geq 3\alpha$. And their
boundedness in $L^p(\mathbb{R}^{2})$
were also obtained, whenever $\beta\gt 3\alpha$, $\frac{2\beta}{2\beta3\alpha}\lt p\lt \frac{2\beta}{3\alpha}$.


812  Infinite Powers and Cohen Reals Medini, Andrea; van Mill, Jan; Zdomskyy, Lyubomyr S.
We give a consistent example of a zerodimensional separable
metrizable space $Z$ such that every homeomorphism of $Z^\omega$
acts like a permutation of the coordinates almost everywhere.
Furthermore, this permutation varies continuously. This shows
that a result of Dow and Pearl is sharp, and gives some insight
into an open problem of Terada. Our example $Z$ is simply the
set of $\omega_1$ Cohen reals, viewed as a subspace of $2^\omega$.


822  Multivariate RankinSelberg Integrals on $GL_4$ and $GU(2,2)$ Pollack, Aaron; Shah, Shrenik
Inspired by a construction by Bump, Friedberg, and Ginzburg of
a twovariable integral representation on $\operatorname{GSp}_4$ for the product
of the standard and spin $L$functions, we give two similar multivariate
integral representations. The first is a threevariable RankinSelberg
integral for cusp forms on $\operatorname{PGL}_4$ representing the product
of the $L$functions attached to the three fundamental representations
of the Langlands $L$group $\operatorname{SL}_4(\mathbf{C})$. The second integral,
which is closely related, is a twovariable RankinSelberg integral
for cusp forms on $\operatorname{PGU}(2,2)$ representing the product of the
degree 8 standard $L$function and the degree 6 exterior square
$L$function.


836  Total Nonnegativity and Stable Polynomials Purbhoo, Kevin
We consider homogeneous multiaffine polynomials whose coefficients
are the Plücker coordinates of a point $V$ of the Grassmannian.
We show that such a polynomial is stable (with respect to the
upper half plane) if and only if $V$ is in the totally nonnegative
part of the Grassmannian. To prove this, we consider an action
of
matrices on multiaffine polynomials. We show that
a matrix $A$ preserves stability of polynomials if and only if
$A$ is totally nonnegative. The proofs are applications of classical
theory of totally nonnegative matrices, and the generalized
PólyaSchur theory of Borcea and Brändén.


848  Quantum Symmetries of Graph $C^*$algebras Schmidt, Simon; Weber, Moritz
The study of graph $C^*$algebras has a long history in operator
algebras. Surprisingly, their quantum symmetries have never been
computed so far. We close this gap by proving that the quantum
automorphism group of a finite, directed graph without multiple
edges acts maximally on the corresponding graph $C^*$algebra.
This shows that the quantum symmetry of a graph coincides with
the quantum symmetry of the graph $C^*$algebra. In our result,
we use the definition of quantum automorphism groups of graphs
as given by Banica in 2005. Note that Bichon gave a different
definition in 2003; our action is inspired from his work. We
review and compare these two definitions and we give a complete
table of quantum automorphism groups (with respect to either
of the two definitions) for undirected graphs on four vertices.


865  Homological Dimensions of Local (Co)homology over Commutative DGrings Shaul, Liran
Let $A$ be a commutative noetherian ring,
let $\mathfrak{a}\subseteq A$ be an ideal,
and let $I$ be an injective $A$module.
A basic result in the structure theory of injective modules states
that
the $A$module $\Gamma_{\mathfrak{a}}(I)$ consisting of $\mathfrak{a}$torsion elements
is also an injective $A$module.
Recently, de Jong proved a dual result: If $F$ is a flat $A$module,
then the $\mathfrak{a}$adic completion of $F$ is also a flat $A$module.
In this paper we generalize these facts to commutative noetherian
DGrings:
let $A$ be a commutative nonpositive DGring such that $\mathrm{H}^0(A)$
is a noetherian ring,
and for each $i\lt 0$, the $\mathrm{H}^0(A)$module $\mathrm{H}^i(A)$
is finitely generated.
Given an ideal $\bar{\mathfrak{a}} \subseteq \mathrm{H}^0(A)$,
we show that the local cohomology functor $\mathrm{R}\Gamma_{\bar{\mathfrak{a}}}$
associated to $\bar{\mathfrak{a}}$ does not increase injective dimension.
Dually, the derived $\bar{\mathfrak{a}}$adic completion functor $\mathrm{L}\Lambda_{\bar{\mathfrak{a}}}$
does not increase flat dimension.


878  Weak Approximation for Points with Coordinates in Rankone Subgroups of Global Function Fields Sun, ChiaLiang
For every affine variety over a global function field, we show
that
the set of its points with coordinates in an arbitrary rankone
multiplicative
subgroup of this function field satisfies the required property
of
weak approximation for finite sets of places of this function
field
avoiding arbitrarily given finitely many places.

