Arrangements of Semicircles on S

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Results on Commutativity of Rings

We establish two theorems on the commutativity of rings with identity.Whileour first result is based on an iteration method,the second deals with centralconditions.     

Boundeness of a Class of Maximal Operators on H~p Spaces on Compact Lie Groups

In this paper we discuss the weak type(H^p,L^p) boundedness of a class of maximal operators T*^ψ and themaximal strong mean boundedness of a family of the operators ｛T^ψ｝ on the atomic H^p spaces on compact Lic groups.Also,we obtain the correspoding convergent results.     

A Note on Property of Cauchy Integral on Classical Domains

In[1],ZhengXueanprovedthat:letRI(n×n)befirstclassicaldomain,Unbecharacteris-ticboundaryofRI,x∈Un,f(x)∈L2(Un).Asz=rx(0≤r<1)→x,Cauchyintegral∫Unf(y)det(I-zy′)-ndyconvergetoafunctioninL2(Un).Inthispaper,wewillfacusourselfonCauchyintegralofL2onclassicaldomains[2]andgetsomeproperties.Themainresultisfollowing:Theorem　LetRbeoneofclassicaldomains,LbecharacteristicboundaryofR,f∈L2(L),H(z,ξ)beCauchykernelofRandF(z)=∫Lf(u)H(z,u)u　z∈R,(1)wheretherightisLebesgueintegral;uist…     

Birkhoff interpolation on unity and on Möbius transform of the roots of unity

In this paper the regularity of two interpolation problems is proved. One uses (0,1,..., r-2,r) interpolation with as nodes Möbius transforms of nth roots of unity with the point z=1 added and the other is concerned with Pál-type interpolation on the pair of polynomials (z+α)ⁿ+(1+α z)ⁿ and (z+α)ⁿ-(1+α z)ⁿ, where 0 < α < 1.     

Note on a Conjecture of Gopakumar-Vafa

We rephrase the Gopakumar-Vafa conjecture on genus zero Gromov-Witten invariants of Calabi-Yau threefolds in terms of the virtual degree of the moduli of pure dimension one stable sheaves and investigate the conjecture for K3 fibred local Calabi-Yau threefolds.     

Some Notes on Solvability of LPDO

The purpose of this paper is to discuss how the lower order terms of a LPDO with multiple characteristics influence the solvability of the operators. We begin with the followiog operator: L(x,D)=D_1~2+x_1~2D_2~2+pD_2+qD_1+c where p,q,c are assumed be complex constants. Theorem 1 The operator L will be locally solvable for any q,c, if either |Re p|<1 or Im p=0.     

Positive Operators à la Aumann-Shapley on Spaces of Functions on D-Lattices

Let L be a σ-complete D-lattice and BV the AL-space of all realvalued, null in zero, functions on L of bounded variation. We prove the existence of a continuous Aumann-Shapley operator on the closed subspace of BV generated by powers of nonatomic σ-additive positive modular measures on L. The integral representation of on a class of functions that correspond to measure games is also exhibited. Dedicated to Professor Paolo De Lucia on the occasion of his 70th birthday.     

Randomization of Q_p spaces on the unit ball of C~n

In this paper, we study the random power series of several complex variables, and give some sufficient conditions for random power series to belong to Qp and Qp,0 spaces by means of their characterizations of Carleson measure. Moreover, we show that such conditions are best possible in some sense.     

Comparison of topologies on ⁎-algebras of locally measurable operators

We consider the local measure topology ${t(\mathcal{M})}$ on the ?-algebra ${LS(\mathcal{M})}$ of all locally measurable operators and on the ?-algebra ${S(\mathcal{M},\tau)}$ of all τ-measurable operators affiliated with a von Neumann algebra ${\mathcal{M}}$ . If τ is a semifinite but not a finite trace on ${\mathcal{M},}$ then one can consider the τ-local measure topology t _τ l and the weak τ-local measure topology t _{w τ l} . We study relationships between the topology ${t(\mathcal{M})}$ and the topologies t _τ l , t _{w τ l} , and the (o)-topology ${t_o(\mathcal{M})}$ on ${LS_h(\mathcal{M})=\{T\in LS(\mathcal{M}): T^\ast=T\}}$ . We find that the topologies ${t(\mathcal{M})}$ and t _τ l (resp. ${t(\mathcal{M})}$ and t _{w τ l} ) coincide on ${S(\mathcal{M},\tau)}$ if and only if ${\mathcal{M}}$ is finite, and ${t(\mathcal{M})=t_o(\mathcal{M})}$ on ${LS_h(\mathcal{M})}$ holds if and only if ${\mathcal{M}}$ is a σ-finite and finite. Moreover, it turns out that the topology t _{τ l} (resp. t _{w τ l} ) coincides with the (o)-topology on ${S_h(\mathcal{M},\tau)}$ only for finite traces. We give necessary and sufficient conditions for the topology ${t(\mathcal{M})}$ to be locally convex (resp., normable). We show that (o)-convergence of sequences in ${LS_h(\mathcal{M})}$ and convergence in the topology ${t(\mathcal{M})}$ coincide if and only if the algebra ${\mathcal{M}}$ is an atomic and finite algebra.     

Spatiality of Derivations on the Algebra of τ-Compact Operators

This paper is devoted to derivations on the algebra S ₀(M, τ) of all τ-compact operators affiliated with a von Neumann algebra M and a faithful normal semi-finite trace τ. The main result asserts that every t _τ -continuous derivation ${D : S_0(M, \tau) \rightarrow S_{0}(M, \tau)}$ is spatial and implemented by a τ-measurable operator affiliated with M, where t _τ denotes the measure topology on S ₀(M, τ). We also show the automatic t _τ -continuity of all derivations on S ₀(M, τ) for properly infinite von Neumann algebras M. Thus in the properly infinite case the condition of t _τ -continuity of the derivation is redundant for its spatiality.     

Remarks on two theorems of Qi-Keng Lu

Two alternate arguments in the framework of intrinsic metrics and measures respectively of part of the proof of a famous theorem due to Qi-Keng Lu on Bergman metric with constant negative holomorphic sectional curvature are presented.A relationship between the Lu constant and the holo- morphic sectional curvature of the Bergman metric is given.Some recent progress of the Yau's porblem on the characterization of domain of holomorphy on which the Bergman metric is K(?)hler-Einstein is described.     

A Note on Pseudo Ideals of Fields

Definition A subring A of a ring R is called a pseudo ideal, if for any r∈R and α∈A, r~2α∈A and αr~2∈A. The subring (R)~2={Σ±r_1~2…r_i~2|r_i∈R, t∈N} is called the square closed ring of R. Lemma The square closed ring of a division ring D is the intersection of all nontrivial pseudo ideals of D. Theorem Ⅰ If a simple ring R with a unit has a nontrivial pseudo ideal A containing an invertible element, R has characteristic p=2. In particular, the necessary condition for a division ring containing a nontrivial pseudo ideal is     

A Note on Stability of Multivariate Distributions

In this note,we give an elementary proof of a characterlzatlon for stabilityof nluuIvarlate dlstrlbutlons by considering a functional equatloll.     

Remarks on ω-domination of discrete subspaces

Abstract

Given a space X, we will say that a class of subsets of X is dominated by a class ? if for any A ∈ , there exists a B ∈ ? such that A ? . In particular, all (closed) discrete subsets of X are countably dominated (which we frequently abbreviate as ω-dominated) if, for any (closed) discrete set D ? X, there exists a countable set B ? X such that D ? . In this paper, we investigate the topological properties of spaces in which (closed) discrete subspaces are dominated either by countable subsets or by Lindelöf subspaces.     

Study on the Structure of Γ-Semihypergroups

In this article, we study Γ-semihypergroups introduced recently. We introduce the hyper versions of Green's relations in Γ-semihypergroups and give some related characterizations. We introduce the n-prime Γ-hyperideal and n-semiprime Γ-hyperideal of a Γ-semihypergroup and show that for any integer n ≥ 2, n-prime Γ-hyperideals are a generalization of prime Γ-ideals. We also give the relationship between n-prime Γ-hyperideals and Γ-hyperideal extensions in Γ-semihypergroups. Then, we deal with prime ideal and introduce the notion of prime radical in a Γ-semihypergroup M, and also, we obtain some results and relations among the prime radicals of M and S, where S is the left operator semihypergroup of M.