An improved estimate is provided for the number of ${{\text{F}}_{q}}$-rational points on a geometrically irreducible, projective, cubic hypersurface that is not equal to a cone.

We study the existence of continuity points for mappings $f\,:\,X\,\times \,Y\,\to \,Z$ whose $x$-sections $Y\,\backepsilon \,y\,\to \,f\left( x,y \right)\,\in \,Z$ are fragmentable and $y$-sections $X\,\backepsilon \,x\,\to \,f\left( x,y \right)\,\in \,Z$ are quasicontinuous, where $X$ is a Baire space and $Z$ is a metric space. For the factor $Y$, we consider two infinite “point-picking” games ${{G}_{1}}\,\left( y \right)$ and ${{G}_{2}}\,\left( y \right)$ defined respectively for each $y\,\in \,Y$ as follows: in the $n$-th inning, Player I gives a dense set ${{D}_{n}}\,\subset \,Y$, respectively, a dense open set ${{D}_{n}}\,\subset \,Y$. Then Player II picks a point ${{y}_{n}}\,\in \,{{D}_{n}}$; II wins if $y$ is in the closure of $\left\{ {{y}_{n}}\,:\,n\,\in \,\mathbb{N} \right\}$, otherwise I wins. It is shown that (i) $f$ is cliquish if II has a winning strategy in ${{G}_{1}}\,\left( y \right)$ for every $y\,\in \,Y$, and (ii) $f$ is quasicontinuous if the $x$-sections of $f$ are continuous and the set of $y\,\in \,Y$ such that II has a winning strategy in ${{G}_{2}}\,\left( y \right)$ is dense in $Y$. Item (i) extends substantially a result of Debs and item (ii) indicates that the problem of Talagrand on separately continuous maps has a positive answer for a wide class of “small” compact spaces.

In this work we introduce a class of discrete groups containing subgroups of abstract translations and dilations, respectively. A variety of wavelet systems can appear as $\pi \left( \Gamma \right)\psi $, where $\pi $ is a unitary representation of a wavelet group and $\Gamma $ is the abstract pseudo-lattice $\Gamma $. We prove a sufficent condition in order that a Parseval frame $\pi \left( \Gamma \right)\psi $ can be dilated to an orthonormal basis of the form $\tau \left( \Gamma \right)\Psi $, where $\tau $ is a super-representation of $\pi $. For a subclass of groups that includes the case where the translation subgroup is Heisenberg, we show that this condition always holds, and we cite familiar examples as applications.

Total embedding distributions have been known for a few classes of graphs. Chen, Gross, and Rieper computed it for necklaces, close-end ladders and cobblestone paths. Kwak and Shim computed it for bouquets of circles and dipoles. In this paper, a splitting theorem is generalized and the embedding distributions of generalized fan graphs are obtained

Let $X$ be a compact metric space. A lower bound for the radius of comparison of the ${{\text{C}}^{*}}$-algebra $\text{C}\left( X \right)$ is given in terms of ${{\dim}_{\mathbb{Q}}}\,X$, where ${{\dim}_{\mathbb{Q}}}\,X$ is the cohomological dimension with rational coefficients. If ${{\dim}_{\mathbb{Q}}}\,X\,=\,\dim\,X\,=\,d$, then the radius of comparison of the ${{\text{C}}^{*}}$-algebra $C\left( X \right)$ is $\max \left\{ 0,\,\left( d\,-\,1 \right)/\,2\,-\,1 \right\}$ if $d$ is odd, and must be either ${d}/{2}\;\,-\,1$ or ${d}/{2}\;\,-\,2$ if $d$ is even (the possibility ${d}/{2}\;\,-\,1$ does occur, but we do not know if the possibility ${d}/{2}\;\,-\,2$ can also occur).

A vector measure result is used to study the complementation of the space $K\left( X,Y \right)$ of compact operators in the spaces $W\left( X,Y \right)$ of weakly compact operators, $CC\left( X,Y \right)$ of completely continuous operators, and $U\left( X,Y \right)$ of unconditionally converging operators. Results of Kalton and Emmanuele concerning the complementation of $K\left( X,Y \right)$ in $L\left( X,Y \right)$ and in $W\left( X,Y \right)$ are generalized. The containment of ${{c}_{0}}$ and ${{\ell }_{\infty }}$ in spaces of operators is also studied.

For Banach spaces $X$ and $Y$, we show that if ${{X}^{*}}$ and $Y$ are weakly sequentially complete and every weakly compact operator from $X$ to $Y$ is compact, then the space of all compact operators from $X$ to $Y$ is weakly sequentially complete. The converse is also true if, in addition, either ${{X}^{*}}$ or $Y$ has the bounded compact approximation property.

In this note, we first give a characterization of super weakly compact convex sets of a Banach space $X$: a closed bounded convex set $K\,\subset \,X$ is super weakly compact if and only if there exists a ${{w}^{*}}$ lower semicontinuous seminorm $P$ with $P\,\ge \,{{\sigma }_{K}}\,\equiv \,{{\sup }_{x\in K}}\left\langle \,\cdot \,,\,x \right\rangle $ such that ${{P}^{2}}$ is uniformly Fréchet differentiable on each bounded set of ${{X}^{*}}$. Then we present a representation theoremfor the dual of the semigroup swcc$\left( X \right)$ consisting of all the nonempty super weakly compact convex sets of the space $X$.

Let ${{\sigma }_{\mathbb{Z}}}\left( k \right)$ be the smallest $n$ such that there exists an identity

$$\left( x_{1}^{2}\,+\,x_{2}^{2}\,+\,\cdot \cdot \cdot \,+\,x_{k}^{2} \right)\,\cdot \,\left( y_{1}^{2}\,+\,y_{2}^{2}\,+\,\cdot \cdot \cdot \,+\,y_{k}^{2} \right)\,=\,f_{1}^{2}\,+\,f_{2}^{2}\,+\,\cdot \cdot \cdot \,+\,f_{n}^{2},$$

${{f}_{1}},...,\,{{f}_{n}}$

${{x}_{1}},...,\,{{x}_{k}}$

${{y}_{1}},...,\,{{y}_{k}}$

${{\sigma }_{\mathbb{Z}}}\left( k \right)\,\ge \,\Omega \left( {{k}^{{6}/{5}\;}} \right)$

We prove a result concerning power series $f\left( Z \right)\,\in \,\mathbb{C}\left[\!\left[ Z \right]\!\right]$ satisfying a functional equation of the form?

1

$$f\left( {{Z}^{d}} \right)\,=\,\sum\limits_{k=1}^{n}{\frac{{{A}_{k}}\left( Z \right)}{{{B}_{k}}\left( Z \right)}\,f{{\left( Z \right)}^{k}}},$$

where ${{A}_{k}}\left( Z \right),\,{{B}_{k}}\left( Z \right)\,\in \,\mathbb{C}\left[ Z \right]$. In particular, we show that if $f\left( Z \right)$ satisfies a minimal functional equation of the above form with $n\,\ge \,2$, then $f\left( Z \right)$ is necessarily transcendental. Towards a more complete classification, the case $n=\,1$ is also considered.

We prove a necessary and sufficient condition on the list of nonzero integers ${{u}_{1}},...,{{u}_{k}}$, $k\,\ge \,2$, under which a monic polynomial $f\,\in \,\mathbb{Z}\left| x \right|$ is expressible by a linear form ${{u}_{1}}\,{{f}_{1}}\,+\,\cdot \cdot \cdot \,+\,{{u}_{k}}\,{{f}_{k}}$ in monic polynomials ${{f}_{1}},...,\,{{f}_{k}}\,\in \,\mathbb{Z}\left| x \right|$. This condition is independent of $f$. We also show that if this condition holds, then the monic polynomials ${{f}_{1}},...,\,{{f}_{k}}$ can be chosen to be irreducible in $\mathbb{Z}\left[ x \right]$.

In this paper, the dimension function of a self-affine generalized scaling set associated with an $n\,\times \,n$ integral expansive dilation $A$ is studied. More specifically, we consider the dimension function of an $A$-dilation generalized scaling set $K$ assuming that $K$ is a self-affine tile satisfying $BK\,=\,\left( K\,+\,{{d}_{1}} \right)\,\cup \,\left( K\,+\,{{d}_{2}} \right)$, where $B\,=\,{{A}^{t}},\,A$ is an $n\,\times \,n$ integral expansive matrix with $\left| \det \,A \right|\,=\,2$, and ${{d}_{1}},\,{{d}_{2}}\,\in \,{{\mathbb{R}}^{n}}$. We show that the dimension function of $K$ must be constant if either $n\,=1$ or 2 or one of the digits is 0, and that it is bounded by $2\left| K \right|$ for any $n$.

The Mahler measure of a nonzero $n$-variable polynomial $P$ is the integral of $\log \,\left| P \right|$ on the unit $n$-torus. A result of Boyd and Lawton says that the Mahler measure of a multivariate polynomial is the limit of Mahler measures of univariate polynomials. We prove the analogous result for different extensions of Mahler measure such as generalized Mahler measure (integrating the maximum of $\log \,\left| P \right|$ for possibly different ${{P}^{'}}\text{s}$), multiple Mahler measure (involving products of $\log \,\left| P \right|$ for possibly different ${{P}^{'}}\text{s}$), and higher Mahler measure (involving ${{\log }^{k}}\,\left| P \right|$).

In this paper we study the existence of periodic solutions of a Volterra type integral equation with infinite heredity. Banach fixed point theorem, Krasnosel'skii's fixed point theorem, and a combination of Krasnosel'skii's and Schaefer's fixed point theorems are employed in the analysis. The combination theorem of Krasnosel'skii and Schaefer requires an a priori bound on all solutions. We employ Liapunov's direct method to obtain such an a priori bound. In the process, we compare these theorems in terms of assumptions and outcomes.

M. Hu and S. Wen considered quasisymmetrically minimal uniform Cantor sets of Hausdorff dimension 1, where at the $K$-th set one removes from each interval $I$ a certain number ${{n}_{k}}$ of open subintervals of length ${{c}_{k}}\left| I \right|$, leaving $\left( {{n}_{k}}\,+\,1 \right)$ closed subintervals of equal length. Quasisymmetrically Moran sets of Hausdorff dimension 1 considered in the paper are more general than uniform Cantor sets in that neither the open subintervals nor the closed subintervals are required to be of equal length.

In this paper we study the notion of equivariant forms introduced in the authors' previous works. In particular, we completely classify all the equivariant forms for a subgroup of $\text{S}{{\text{L}}_{2\left( \mathbb{Z} \right)}}$ by means of the cross-ratio, weight 2 modular forms, quasimodular forms, as well as differential forms of a Riemann surface and sections of a canonical line bundle.

In this paper we study uniqueness of entire functions sharing a non-zero finite value with linear differential polynomials and address a result of W.Wang and P. Li.

We give sufficient conditions for the following problem: given a topological space $X$, a metric space $Y$, a subspace $Z$ of $Y$, and a continuous map $f$ from $X$ to $Y$, is it possible, by applying to $f$ an arbitrarily small perturbation, to ensure that $f\left( {{X}^{'}} \right)$ does not meet $Z$? We also give a relative variant: if $f\left( X\prime \right)$ does not meet $Z$ for a certain subset ${X}'\subset X$, then we may keep $f$ unchanged on ${X}'$. We also develop a variant for continuous sections of fibrations and discuss some applications to matrix perturbation theory.

Let $A$ be a Banach algebra and let $\pi :\,A\,\to \,\mathcal{L}\left( H \right)$ be a continuous representation of $A$ on a separable Hilbert space $H$ with dim $H\,=\,\text{m}$. Let ${{\pi }_{ij}}$ be the coordinate functions of $\pi $ with respect to an orthonormal basis and suppose that for each $1\,\le \,j\,\le \,\text{m,}\,{{C}_{j}}\,=\,\sum\nolimits_{i=1}^{\text{m}}{\left\| {{\pi }_{ij}} \right\|}{{A}^{*}}\,<\,\infty $ and ${{\sup }_{j}}\,{{C}_{j}}\,<\,\infty $. Under these conditions, we call an element $\overline{\Phi }\,\in \,{{\iota }^{\infty }}\,\left( \mathfrak{m},\,{{A}^{**}} \right)$ left $\pi $-invariant if $a\,\cdot \overline{\Phi }\,={{\,}^{^{t}\pi }}\left( a \right)\overline{\Phi }$ for all $a\in A$ In this paper we prove a link between the existence of left $\pi $-invariant elements and the vanishing of certain Hochschild cohomology groups of $A$. Our results extend an earlier result by Lau on $F$-algebras and recent results of Kaniuth, Lau, Pym, and and the second author in the special case where $\pi :\,A\,\to \text{C}$ is a non-zero character on $A$.

We prove the non-existence of real hypersurfaces in complex projective space whose structure Jacobi operator is Lie $\mathbb{D}$-parallel and satisfies a further condition.