Let $(R,\mathfrak{m})$ denote a local Cohen–Macaulay ring and $I$ a non-nilpotent ideal of $R$. The purpose of this article is to investigate Faltings’ finiteness dimension ${{f}_{I}}(R)$ and the equidimensionalness of certain homomorphic images of $R$. As a consequence we deduce that ${{f}_{I}}(R)=\max \{1,\text{ht}I\}$, and if $\text{mAs}{{\text{s}}_{R}}(R/I)$ is contained in $\text{As}{{\text{s}}_{R}}(R)$, then the ring $R/I+{{\bigcup }_{n\ge 1}}(0{{:}_{R}}{{I}^{n}})$ is equidimensional of dimension dim $R-1$. Moreover, we will obtain a lower bound for injective dimension of the local cohomology module $H_{I}^{\text{ht}I}(R)$, in the case where $(R,\mathfrak{m})$ is a complete equidimensional local ring.

Let $R$ be a commutative ring with identity. The co-annihilating-ideal graph of $R$, denoted by ${{\mathcal{A}}_{R}}$, is a graph whose vertex set is the set of all non-zero proper ideals of $R$ and two distinct vertices $I$ and $J$ are adjacent whenever $\text{Ann}\left( I \right)\,\cap \,\text{Ann}\left( J \right)\,=\,\left\{ 0 \right\}$. In this paper we initiate the study of the co-annihilating ideal graph of a commutative ring and we investigate its properties.

We investigate quantum group generalizations of various density results from Fourier analysis on compact groups. In particular, we establish the density of characters in the space of fixed points of the conjugation action on ${{L}^{2}}(\mathbb{G})$ and use this result to show the $\text{wea}{{\text{k}}^{\star }}$ density and normal density of characters in $Z{{L}^{\infty }}(\mathbb{G})$ and $ZC(\mathbb{G})$, respectively. As a corollary, we partially answer an open question of Woronowicz. At the level of ${{L}^{1}}(\mathbb{G})$, we show that the center $~z({{L}^{1}}(\mathbb{G}))$ is precisely the closed linear span of the quantum characters for a large class of compact quantum groups, including arbitrary compact Kac algebras. In the latter setting, we show, in addition, that $~z({{L}^{1}}(\mathbb{G}))$ is a completely complemented $~z({{L}^{1}}(\mathbb{G}))$-submodule of ${{L}^{2}}(\mathbb{G})$.

Let $(X,d)$ be a metric space and let $J\subseteq [0,\infty )$ be nonempty. We study the structure of the arbitrary intersections of Lipschitz algebras and define a special Banach subalgebra of ${{\cap }_{\gamma \in J\,}}\text{Li}{{\text{p}}_{\gamma \,}}X$, denoted by $\text{ILi}{{\text{p}}_{J}}X$. Mainly, we investigate the $C$-character amenability of $\text{ILi}{{\text{p}}_{J}}X$, in particular Lipschitz algebras. We address a gap in the proof of a recent result in this field. Then we remove this gap and obtain a necessary and sufficient condition for $C$-character amenability of $\text{ILi}{{\text{p}}_{J}}X$, specially Lipschitz algebras, under an additional assumption.

Let $H$ be a group. The co-maximal graph of subgroups of $H$, denoted by $\Gamma \left( H \right)$, is a graph whose vertices are non-trivial and proper subgroups of $H$ and two distinct vertices $L$ and $K$ are adjacent in $\Gamma \left( H \right)$ if and only if $H\,=\,LK$. In this paper, we study the connectivity, diameter, clique number, and vertex chromatic number of $\Gamma \left( H \right)$. For instance, we show that if $\Gamma \left( H \right)$ has no isolated vertex, then $\Gamma \left( H \right)$ is connected with diameter at most 3. Also, we characterize all finitely groups whose co-maximal graphs are connected. Among other results, we show that if $H$ is a finitely generated solvable group and $\Gamma \left( H \right)$ is connected, and moreover, the degree of a maximal subgroup is finite, then $H$ is finite. Furthermore, we show that the degree of each vertex in the co-maximal graph of a general linear group over an algebraically closed field is zero or infinite.

We prove the existence of a (in fact many) holomorphic function $f$ in ${{\mathbb{C}}^{d}}$ such that, for any $a\ne 0$, its translations $f(\cdot +na)$ are dense in $H({{\mathbb{C}}^{d}})$.

We compute the cohomology of the right generalised projective Stiefel manifolds. Following this, we discuss some easy applications of the computations to the ranks of complementary bundles and bounds on the span and immersibility.

In this paper, we show that the Möbius invariant function space ${{\mathcal{Q}}_{p}}$ can be generated by variant Dirichlet type spaces ${{\mathcal{D}}_{\mu ,p}}$ induced by finite positive Borel measures $\mu $ on the open unit disk. A criterion for the equality between the space ${{\mathcal{D}}_{\mu ,p}}$ and the usual Dirichlet type space ${{\mathcal{D}}_{p}}$ is given. We obtain a sufficient condition to construct different ${{\mathcal{D}}_{\mu ,p}}$ spaces and provide examples. We establish decomposition theorems for ${{\mathcal{D}}_{\mu ,p}}$ spaces and prove that the non-Hilbert space ${{\mathcal{Q}}_{p}}$ is equal to the intersection of Hilbert spaces ${{\mathcal{D}}_{\mu ,p}}$. As an application of the relation between ${{\mathcal{Q}}_{p}}$ and ${{\mathcal{D}}_{\mu ,p}}$ spaces, we also obtain that there exist different ${{\mathcal{D}}_{\mu ,p}}$ spaces; this is a trick to prove the existence without constructing examples.

All finite simple self 2-distance graphs with no square, diamond, or triangles with a common vertex as subgraph are determined. Utilizing these results, it is shown that there is no cubic self 2-distance graph.

In a previous work, we associated a complete differential graded Lie algebra to any finite simplicial complex in a functorial way. Similarly, we also have a realization functor fromthe category of complete differential graded Lie algebras to the category of simplicial sets. We have already interpreted the homology of a Lie algebra in terms of homotopy groups of its realization. In this paper, we begin a dictionary between models and simplicial complexes by establishing a correspondence between the Deligne groupoid of the model and the connected components of the finite simplicial complex.

In this paper, we give a new definition of radicals of Green’s relations in an ordered semigroup and characterize left regular (right regular), intra regular ordered semigroups by radicals of Green’s relations. We also characterize the ordered semigroups that are unions and complete semilattices of $\text{t}$-simple ordered semigroups.

We use the classical Perron envelope method to show a general existence theorem to degenerate complex Monge–Ampére type equations on compact Kähler manifolds.

In this paper, a newnotion of scalar curvature for a Finsler metric $F$ is introduced, and two conformal invariants $Y(M,F)$ and $C(M,F)$ are defined. We prove that there exists a Finsler metric with constant scalar curvature in the conformal class of $F$ if the Cartan torsion of $F$ is sufficiently small and $Y(M,F)C(M,F)<Y({{\mathbb{S}}^{n}})$ where $Y({{\mathbb{S}}^{n}})$ is the Yamabe constant of the standard sphere.

Let $G$ denote a reductive algebraic group over $\mathbb{C}$ and $x$ a nilpotent element of its Lie algebra $\mathfrak{g}$. The Springer variety ${{B}_{x}}$ is the closed subvariety of the flag variety $B$ of $G$ parameterizing the Borel subalgebras of $\mathfrak{g}$ containing $x$. It has the remarkable property that the Weyl group $W$ of $G$ admits a representation on the cohomology of ${{B}_{x}}$ even though $W$ rarely acts on ${{B}_{x}}$ itself. Well-known constructions of this action due to Springer and others use technical machinery from algebraic geometry. The purpose of this note is to describe an elementary approach that gives this action when $x$ is what we call parabolic-surjective. The idea is to use localization to construct an action of $W$ on the equivariant cohomology algebra $H_{s}^{*}({{B}_{x}})$, where $S$ is a certain algebraic subtorus of $G$. This action descends to ${{H}^{*}}({{B}_{x}})$ via the forgetful map and gives the desired representation. The parabolic-surjective case includes all nilpotents of type $A$ and, more generally, all nilpotents for which it is known that $W$ acts on $H_{s}^{*}({{B}_{x}})$ for some torus $S$. Our result is deduced from a general theorem describing when a group action on the cohomology of the ûxed point set of a torus action on a space lifts to the full cohomology algebra of the space.

Let $P$ be a finite $\text{N}$-free poset. We consider the hypergraph $H\left( P \right)$ whose vertices are the elements of $P$ and whose edges are the maximal intervals of $P$. We study the dual König property of $H\left( P \right)$ in two subclasses of $\text{N}$-free class.

Let $1\le p<\infty $, and let $G$ be a discrete group. We give a sufficient and necessary condition for weighted translation operators on the Lebesgue space ${{\ell }^{p}}(G)$ to be densely disjoint hypercyclic. The characterization for the dual of a weighted translation to be densely disjoint hypercyclic is also obtained.

In this paper, double commutativity and the reverse order law for the core inverse are considered. Then new characterizations of the Moore–Penrose inverse of a regular element are given by one-sided invertibilities in a ring. Furthermore, the characterizations and representations of the core and dual core inverses of a regular element are considered.

Let $R$ be a prime ring with extended centroid $\text{C,Q}$ maximal right ring of quotients of $R$, $RC$ central closure of $R$ such that ${{\dim}_{C}}(RC)>4,f({{X}_{1}},...,{{X}_{n}})$ a multilinear polynomial over $C$ that is not central-valued on $R$, and $f(R)$ the set of all evaluations of the multilinear polynomial $f({{X}_{1}},...,{{X}_{n}})$ in $R$. Suppose that $G$ is a nonzero generalized derivation of $R$ such that ${{G}^{2}}(u)u\in C$ for all $u\in f(R)$. Then one of the following conditions holds:

• (i) there exists $a\in \text{Q}$ such that ${{a}^{2}}=0$ and either $G(x)=ax$ for all $x\in R$or $G(x)=xa$ for all $x\in R$;

• (ii) there exists $a\in \text{Q}$ such that $0\ne {{a}^{2}}\in C$ and either $G(x)=ax$ for all $x\in R$ or $G(x)=xa$ for all $x\in R$ and $f{{({{X}_{1}},...,{{X}_{n}})}^{2}}$is central-valued on $R$;

• (iii) char $(R)=2$ and one of the following holds:

• (a) there exist $a,b,\in \text{Q}$ such that $G(x)=ax+xb$ for all $x\in R$ and ${{a}^{2}}={{b}^{2}}\in C$;

• (b) there exist $a,b,\in \text{Q}$ such that $G(x)=ax+xb$ for all $x\in R,\,{{a}^{2}},{{b}^{2}}\in C$ and $f{{({{X}_{1}},...,{{X}_{n}})}^{2}}$ is central-valued on $R$;

• (c) there exist $a\in \text{Q}$ and an $X$-outer derivation $d$ of $R$ such that $G(x)=ax+d(x)$ for all $x\in R,{{d}^{2}}=0$ and ${{a}^{2}}+d(a)=0$;

• (d) there exist $a\in \text{Q}$ and an $X$-outer derivation $d$ of $R$ such that $G(x)=ax+d(x)$ for all $x\in R,\,{{d}^{2}}=0,\,{{a}^{2}}+d(a)\in C$ and $f{{({{X}_{1}},...,{{X}_{n}})}^{2}}$ is central-valued on $R$.

Moreover, we characterize the form of nonzero generalized derivations $G$ of $R$ satisfying ${{G}^{2}}(x)=\lambda x$ for all $x\in R$, where $\lambda \in C$.

We identify when a tubular group (the fundamental group of a finite graph of groups with ${{\mathbb{Z}}^{2}}$ vertex and $\mathbb{Z}$ edge groups) is free by cyclic and show, using Wise’s equitable sets criterion, that every tubular free by cyclic group acts freely on a $\text{CAT}\left( 0 \right)$ cube complex.

We prove Lawton's conjecture about the upper bound on themeasure of the set on the unit circle on which a complex polynomial with a bounded number of coefficients takes small values. Namely, we prove that Lawton's bound holds for polynomials that are not necessarily monic. We also provide an analogous bound for polynomials in several variables. Finally, we investigate the dependence of the bound on the multiplicity of zeros for polynomials in one variable.