A Strict Version of the Non-commutative Urysohn Lemma

Given a pair , of -commuting, hereditary -subalgebras of a unital -algebra , such that is -unital and , there is an element in , with , such that is strictly positive in and is strictly positive in in . Moreover, is strictly positive in in .

     

A Note on a Matrix Version of the Farkas Lemma

A linear polyomial non-negative on the non-negativity domain of finitely many linear polynomials can be expressed as their non-negative linear combination. Recently, under several additional assumptions, Helton, Klep, and McCullough extended this result to matrix polynomials. The aim of this article is to study which of these additional assumptions are really necessary.     

A Brody theorem for orbifolds

We study the Kobayashi pseudodistance for orbifolds, proving an orbifold version of Brody’s theorem and classifying which one-dimensional orbifolds are hyperbolic.     

A proof of the Morse-Bott Lemma

It is often said that the Morse-Bott Lemma can be viewed as a “parameterized” Morse Lemma, and its proof should follow from the differentiability of the methods used to prove the Morse Lemma. The goal of this expository paper is to fill in the details. We present Palais' proof of the Morse Lemma using Moser's path method, which yields the necessary differentiability.     

Bihali引理的证明

根据Bihali引理可以确定微分方程解存在的更大一些的区间.该引理显然是十分重要的,然而目前找不到这个引理的证明.本文给出了一种证明.并举实例说明了这个引理的重要性.     

On a Vector Version of a Fundamental Lemma of J. L. Lions

Let ? be a bounded and connected open subset of R~N with a Lipschitzcontinuous boundary,the set ? being locally on the same side of ??.A vector version of a fundamental lemma of J.L.Lions,due to C.Amrouche,the first author,L.Gratie and S.Kesavan,asserts that any vector field v =(vi) ∈(D′(?))~N,such that all the components 1/2(?_jv_i + ?_iv_j),1 ≤ i,j ≤ N,of its symmetrized gradient matrix field are in the space H~(-1)(?),is in effect in the space(L~2(?))~N.The objective of this paper is to show that this vector version of J.L.Lions lemma is equivalent to a certain number of other properties of interest by themselves.These include in particular a vector version of a well-known inequality due to J.Neˇcas,weak versions of the classical Donati and Saint-Venant compatibility conditions for a matrix field to be the symmetrized gradient matrix field of a vector field,or a natural vector version of a fundamental surjectivity property of the divergence operator.     

Schwarz引理的一个注记

本文中,基于幅角原理和同论理论紧密联系的想法,我们对单复变中经典的Sdlwarz引理给出了一个新的证明.同时,运用同样的方法,我们把Schwarz引理推广到亚纯函数和多连通区域的情形.     

A Note on the Five Lemma

We formulate and prove a “five lemma”, which unifies two independent generalizations of the classical five lemma in an abelian category: the five lemma in a (modular) semi-exact category in the sense of M. Grandis, and the five lemma in a pointed regular protomodular category in the sense of D. Bourn.     

A Generalized Schwarz Lemma

In this paper,we establish a boundary Schwarz Lemma for holomorphic mapping on the generalized complex ellipsoid in Cn.     

A multilinear Phelps' Lemma

We prove a multilinear version of Phelps' Lemma: if the zero sets of multilinear forms of norm one are `close', then so are the multilinear forms.

     

Morse引理的一个推广

设E_n是在0∈Rⁿ的C^∞函数芽环,M是En中唯一的极大理想.如果f∈M²且其二阶Hessain是非退化的,则f同构于它的二阶Hessain,这就是著名的Morse引理.本文将讨论两个变元的C^∞函数芽,得到:(1)若f∈M³?E_xy,且其三阶Hessain是非退化的,则f同构于它的三阶Hessain.(2)若f∈M⁴?E_xy     

A multi-point Schwarz-Pick Lemma

We state and prove a general version of the Schwarz-Pick Lemma that involves more than two points in the hyperbolic plane and with appears to contain all known variations of the classical result. We give some applications to complex function theory and then discuss our result in the context of the Pick-Nevanlinna Theorem.     

A general Fatou Lemma

A general Fatou Lemma is established for a sequence of Gelfand integrable functions from a vector Loeb space to the dual of a separable Banach space or, with a weaker assumption on the sequence, a Banach lattice. A corollary sharpens previous results in the finite-dimensional setting even for the case of scalar measures. Counterexamples are presented to show that the results obtained here are sharp in various aspects. Applications include systematic generalizations of the distribution of correspondences from the case of scalar Loeb spaces to the case of vector Loeb spaces and a proof of the existence of a pure strategy equilibrium in games with private and public information and with compact metric action spaces.     

A Schwarz Lemma for the Symmetrized Bidisc

Let be an analytic function from D to the symmetrized bidisc We show that if (0) = (0,0) and () = (s, p) in the interiorof , then Moreover, the inequality is sharp: we give an explicit formulafor a suitable in the event that the inequality holds withequality. We show further that the inverse hyperbolic tangentof the left-hand side of the inequality is equal to both theCaratheodory distance and the Kobayashi distance from (0,0)to (s, p) in int      

A short proof of the Collapsing Walls Lemma

In this short note we give a simple geometric proof of the Collapsing Walls Lemma given by Pak and Pinchasi (2012) in [1]. Our arguments work in spaces of constant curvature.     

A note on Bailey's Lemma

Combining the qa-binomial theorem in the version of J. Cigler (Monatsh. Math. 88, 87–105 (1979)) with the ε-technique of L. J. Rogers (G. E. Andrews, Math. Chronicle, 11, 1–15, 1982) a short operator proof of a significant special case of Bailey's Lemma is given.     

Higher-Dimensional Representations of the Reflection Equation Algebra

We consider a new method for constructing finite-dimensional irreducible representations of the reflection equation algebra. We construct a series of irreducible representations parameterized by Young diagrams. We calculate the spectra of central elements s _k=Tr_q L ^k of the reflection equation algebra on q-symmetric and q-antisymmetric representations. We propose a rule for decomposing the tensor product of representations into irreducible representations.