an efficient laplace transform solution for multiaquifer systems an efficient numerical algorithm is developed for groundwater flow in multiaquifer systems the method is based on herrera s formulation which eliminates the need of explicitly modeling aquitards laplace transform is applied to the governing integrodifferential equations which removes not only the time dependence in the solution system but also the integral expression the final system is a set of nontransient linear partial differential equations in two spatial dimensions a regular finite difference method is used for its solution the solution in the laplace transform domain is then inverted to the time domain using either a slow or a quick scheme depending on the requirement of speed and accuracy examples of a two aquifer one aquitard system involving radial and regional geometries are examimed

gleason s theorem for rectangular jbw triples a jbw triple b is said to be rectangular if there exists a w algebra a and a pair p q of centrally equivalent elements of the complete orthomodular lattice of projections in a such that b is isomorphic to the jbw triple paq any weak closed injective operator space provides an example of a rectangular jbw triple the principal order ideal of the complete lattice of centrally equivalent pairs of projections in a w algebra a generated by p q forms a complete lattice that is order isomorphic to the complete lattice of weak closed inner ideals in b and to the complete lattice of structural projections on b although not itself in general orthomodular possesses a complementation that allows for definitions of orthogonality centre and central orthogonality to be given a less familiar notion in lattice theory that is well known in the theory of jordan algebras and jordan triple systems is that of rigid collinearity of a pair e2 f2 and e2 f2 of elements of this is defined and characterized in terms of properties of a w algebra a is sometimes thought of as providing a model for a statistical physical system in this case b or equivalently paq may be thought of as providing a model for a fixed sub system of that represented by a therefore may be considered to represent the set consisting of a particular kind of sub system of that represented by paq central orthogonality and rigid collinearity of pairs of elements of may be regarded as representing two different types of disjointness the former classical disjointness and the latter decoherence of the two sub systems it is therefore natural to consider bounded measures m on that are additive on centrally orthogonal and rigidly collinear pairs of elements using results of j d m wright it is shown that provided that neither of the two hereditary sub w algebras pap and qaq of a has a weak closed ideal of type i2 such measures are precisely those that are the restrictions of bounded sesquilinear functionals m on pap qaq with the property that the action of the centroid z b of b commutes with the adjoint operation when b is a complex hilbert space of dimension greater than two this result reduces to gleason s theorem

local superlinearity and sublinearity for the p laplacian we study the existence nonexistence and multiplicity of positive solutions for a family of problems updelta p u f lambda x u u in w 0 1 p upomega where is a bounded domain in mathbb r n n p and 0 is a parameter the family we consider includes the well known nonlinearities of ambrosetti brezis cerami type in a more general form namely lambda a x u q b x u r where 0 leqslant q p 1 r leqslant p 1 here the coefficient a x is assumed to be nonnegative but b x is allowed to change sign even in the critical case preliminary results of independent interest include the extension to the p laplacian context of the brezis nirenberg result on local minimization in w 0 1 p text and c 0 1 a c 1 alpha estimate for equations of the form updelta p u h x u with h of critical growth a strong comparison result for the p laplacian and a variational approach to the method of upper lower solutions for the p laplacian

an alternative daugavet property abstract we introduce a strictly weaker version of the daugavet property as follows a banach space x has this alternative daugavet property adp in short if the norm identity ade max 1 id t 1 t holds for all rank one operators t x x in such a case all weakly compact operators on x also satisfy ade we give some geometric characterizations of the alternative daugavet property in terms of the space and its successive duals we prove that the adp is stable for c0 l1 and l sums and characterize when some vector valued function spaces have the property finally we show that a c algebra or the predual of a von neumann algebra has the adp if and only if its atomic projection respectively the atomic projection of the algebra are central we also establish some geometric properties of jb triples and characterize jb triples possessing the adp and the daugavet property

the central hull and central kernel in jbw triples abstract the complete lattice i a of weak closed inner ideals in a jbw triple a has as its centre the complete boolean algebra z i a of weak closed ideals in a the annihilator l of the subset l of a consists of elements b of a for which l b a is equal to zero and the kernel ker l of l consists of those elements b in a for which l b l is equal to zero for each element j of i a j also lies in i a and a enjoys the generalized peirce decomposition a j m j j 1 where j 1 is the intersection of the kernels of j and j to investigate the properties of the weak closed subspace j 1 of a which is not in general a subtriple the notions of the central hull c l and central kernel k l of a subspace l are introduced these are respectively the smallest element of z i a containing l and the largest element of z i a contained in l for any element j of i a the relationships that exist between the central hull and central kernel of j and j are examined and it is shown that j 1 j is the weak closed ideal k j that j 1 j is the weak closed ideal k j and when j is a peirce inner ideal that j 1 is the weak closed ideal k j m k j

orthogonality preservers in c algebras jb algebras and jb triples abstract we study orthogonality preserving operators between c algebras jb algebras and jb triples let t a e be an orthogonality preserving bounded linear operator from a c algebra to a jb triple satisfying that t 1 d is a von neumann regular element then t a e 2 r d every element in t a and d operator commute in the jb algebra e 2 r d and there exists a triple homomorphism s a e 2 r d such that t l d r d s where r d denotes the range tripotent of d in e an analogous result for a being a jb algebra is also obtained when t a b is an operator between two c algebras we show that denoting h t 1 then t orthogonality preserving if and only if there exists a triple homomorphism s a b satisfying h s z s z h h s z s z h and t z l h r h s z 1 2 h r h s z s z r h h this allows us to prove that a bounded linear operator between two c algebras is orthogonality preserving if and only if it preserves zero triple products

linear invariance of locally biholomorphic mappings in the unit ball of a jb triple abstract we study the notion of linear invariance on the unit ball of a j b triple x and we obtain some connection between the norm order of a linear invariant family and the starlikeness of order 1 2 also we give some result concerning the radius of univalence of some linear invariant families finally if the dimension of x is finite and if the norm order of a linear invariant family is finite then we prove the normality of the linear invariant family and we also obtain upper bounds on the distortion and the growth of mappings in a linear invariant family with specified norm order in particular our results are valid for the classical cartan domains and the unit polydisc

the lattice of weak closed inner ideals in a w algebra the family of centrally equivalent pairs of projections in a w algebra a forms a complete lattice that is order isomorphic to the complete lattice of weak closed inner ideals in a and to the complete lattice of structural projections on a furthermore the set of symmetric elements of is order isomorphic to the complete orthomodular lattice of projections in a although not itself in general orthomodular possesses a complementation that allows for definitions of orthogonality centre and central orthogonality to be given a less familiar notion in lattice theory that is well known in the theory of jordan algebras and jordan triple systems is that of rigid collinearity of a pair e1 f1 and e2 f2 of elements of this is defined and characterized in terms of properties of

multilayered leaky aquifer systems 2 boundary element solutions the boundary element algorithm for the multilayered leaky aquifer system of neuman witherspoon and herrera is presented by applying the laplace transform to the integrodifferential equations of herrera a set of coupled two dimensional elliptic equations results the boundary integral representation is derived from green s theorem green s functions governed by an adjoint system of the original governing equations are found from the pumping well solutions given in part 1 by a coefficient exchange the resultant numerical system requires a discretization only at the boundaries of the planar aquifers and is free from aquitard unknowns several numerical examples including one dimensional flow pumping well problems and two dimensional problems are provided for the purpose of validation and demonstration

existence of nonoscillatory solutions to neutral dynamic equations on time scales abstract in this paper we give an analogue of the arzela ascoli theorem on time scales then we establish the existence of nonoscillatory solutions to the neutral dynamic equation x t p t x g t f t x h t 0 on a time scale to dwell upon the importance of our results three interesting examples are also included

dunford pettis properties hilbert spaces and projective tensor products we study complete continuity properties of operators onto 2 and prove several results in the dunford pettis theory of jb triples and their projective tensor products culminating in characterisations of the alternative dunford pettis property for e f where e and f are jb triples

images of contractive projections on operator algebras it is shown that if p is a weak continuous contractive projection on a jbw triple m then p m is of type i or semifinite respectively if m is of the corresponding type we also show that p m has no infinite spin part if m is a type i von neumann algebra

weakly compact orthogonality preservers on c algebras we establish a complete description of weakly compact orthogonality preserving operators from a c algebra a or a jb algebra to a jb triple e we prove that any such operator is the sum of a series of mutually orthogonal triple homomorphisms from a to a certain peirce 2 subspace of e multiplied by a mutually orthogonal norm null sequence in e which enjoy certain operator commutativity relations

non periodic averaging principles for measure functional differential equations and functional dynamic equations on time scales involving impulses abstract we present a non periodic averaging principle for measure functional differential equations and using the correspondence between solutions of measure functional differential equations and solutions of functional dynamic equations on time scales see federson et al 2012 8 we obtain a non periodic averaging result for functional dynamic equations on time scales moreover using the relation between measure functional differential equations and impulsive measure functional differential equations we get a non periodic averaging theorem for these equations also it is a known fact that we can relate impulsive measure functional differential equations and impulsive functional dynamic equations on time scales see federson et al 2013 9 therefore applying this correspondence to our averaging principle we obtain a non periodic averaging theorem for impulsive functional dynamic equations on time scales

automatic continuity of derivations on c algebras and jb triples abstract we introduce the notion of banach jordan triple modules and determine the precise conditions under which every derivation from a jb triple e into a banach jordan triple e module is continuous in particular every derivation from a real or complex jb triple into its dual space is automatically continuous motivating the study which we have carried out elsewhere of weakly amenable jb triples specializing to c algebras leads to a unified treatment of derivations and jordan derivations into modules shedding light on a celebrated theorem of barry johnson

on the facial structure of the unit ball in the dual space of a jb triple it is shown that every proper weak closed face of the closed unit ball e 1 in the dual space of a jb triple e coincides with set of all elements in the unit sphere of e attaining their norm at a unique compact tripotent in e in particular every proper weak closed face of the closed unit ball e 1 is weak semi exposed this result provides an affirmative answer to a conjecture posed over 20 years ago

operator space structure of jc triples and tros i we embark upon a systematic investigation of operator space structure of jc triples via a study of the tros ternary rings of operators they generate our approach is to introduce and develop a variety of universal objects including universal tros by which means we are able to describe all possible operator space structures of a jc triple via the concept of reversibility we obtain characterisations of universal tros over a wide range of examples we apply our results to obtain explicit descriptions of operator space structures of cartan factors regardless of dimension

boundedness of solutions of measure differential equations and dynamic equations on time scales abstract in this paper we investigate the boundedness results for measure differential equations in order to obtain our results we use the correspondence between these equations and generalized odes furthermore we prove our results concerning boundedness of solutions for dynamic equations on time scales using the fact that these equations represent a particular case of measure differential equations

projective completions of jordan pairs part i the generalized projective geometry of a lie algebra abstract we prove that the projective completion x x of the jordan pair g 1 g 1 corresponding to a 3 graded lie algebra g g 1 g 0 g 1 can be realized inside the space f of inner 3 filtrations of g in such a way that the remoteness relation on x x corresponds to transversality of flags this realization is used to give geometric proofs of structure results which will be used in part ii of this work in order to define on x and x the structure of a smooth manifold in arbitrary dimension and over general base fields or rings

measures on the lattice of closed inner ideals in a spin triple two elements j and k of the complete lattice i a of weak closed inner ideals in a jbw triple a are said to be centrally orthogonal if there exists a weak closed ideal i in a such that a2 j a2 i and a2 k a0 i and are said to be rigidly collinear when a2 j a1 k and a2 k a1 j where for j equal to 0 1 or 2 aj i aj j and aj k are the components in the generalized peirce decomposition of a relative to the weak closed inner ideals i j and k respectively a measure m on i a is a mapping from i a to c such that if j and k are either centrally orthogonal or rigidly collinear thenmj k mj mk a complex hilbert space a endowed with a conjugation possesses a triple product and norm with respect to which it forms a jbw triple known as a spin triple in this paper the structure of the complete lattice i a of closed inner ideals in a spin triple a and the measures on it are investigated it is shown that if the dimension of a is greater than 5 then there are no non zero measures on i a when the dimension of a is 5 non zero measures exist and up to multiplication by a constant a unique measure exists that is invariant under automorphisms of a when the dimension of a is 4 then a is triple isomorphic to the w algebra of 2 2 complex matrices in this case results of bunce and wright are used to show that there is an uncountable number of measures on i a the situation when the dimension of a is less than 4 is also described

geometric characterization of tripotents in real and complex jb triples abstract we establish a geometric characterization of tripotents in real and complex jb triples as a consequence we obtain an alternative proof of kaup s banach stone theorem for jb triples

a conjugate gradient finite element model of flow for large multiaquifer systems a quasi three dimensional finite element model based on the conjugate gradient technique is developed and applied to the analysis of subsurface flow occurring in complex heterogeneous multiaquifer systems transient leakage across the aquitards is fully taken into consideration using the convolution approach originally derived by herrera 1970 the convolution integrals enhance the favorable features of the modified conjugate gradients mcg which prove to be a very efficient tool for the solution of the integrodifferential model the high performance of mcg results from two combined factors 1 the diagonal dominance of the assembled finite element matrix which is emphasized by the integral contributions 2 the essential reducibility of the matrix for a wide range of time step values which is due to the virtual decoupling of the aquifer equations the preconditioning of the conjugate gradient scheme is therefore improved and a good convergence occurs after a number of iterations smaller than n n n and n being the overall number of nodes and aquifers respectively the computational cost of the model is generally low and its relative efficiency tends to increase for small to moderate time steps and for complex multiaquifer systems where several interconnected aquifers are simulated

state spaces of jb triples an atomic decomposition is proved for banach spaces which satisfy some affine geometric axioms compatible with notions from the quantum mechanical measuring process this is then applied to yield under appropriate assumptions geometric characterizations up to isometry of the unit ball of the dual space of a jb triple and up to complete isometry of one sided ideals in c algebras

holomorphic automorphisms of continuous products of balls we study continuous product domains in the space cal c omega e of all continuouse valued functions on omega where omega is a compact hausdorff topological space and e is an arbitrary jb triple and discuss the group of holomorphic automorphisms of domains of that type

boundary element solution for stochastic groundwater flow random boundary condition and recharge this paper presents an integral equation technique for solving stochastic boundary value problems in groundwater flow the aquifer considered has deterministic hydraulic conductivity but is subject to random boundary condition and domain recharge using the distribution of fictitious sources and dipoles stochastic integral equations for the mean and covariance of head and flux are derived an iterative boundary element technique is applied for numerical solution two one dimensional examples are examined and compared with exact solution a two dimensional problem is then presented

trace order and a distortion theorem for linearly invariant families on the unit ball of a finite dimensional jb triple abstract we give a distortion theorem for linearly invariant families on the unit ball b of a finite dimensional jb triple x by using the trace order the exponents in the distortion bounds depend on the bergman metric at 0 further we introduce a new definition for the trace order of a linearly invariant family on b based on a jacobian argument we also construct an example of a linearly invariant family on b which has minimum trace order and is not a subset of the normalized convex mappings of b for dim x 2 finally we prove a regularity theorem for linearly invariant families on b all four types of classical cartan domains are the open unit balls of jb triples and the same holds for any finite product of these domains thus the unit balls of jb triples are natural generalizations of the unit disc in c and we have a setting in which a large number of bounded symmetric homogeneous domains may be studied simultaneously

low rank compact operators and tingley s problem abstract let e and b be arbitrary weakly compact jb triples whose unit spheres are denoted by s e and s b respectively we prove that every surjective isometry f s e s b admits an extension to a surjective real linear isometry t e b this is a complete solution to tingley s problem in the setting of weakly compact jb triples among the consequences we show that if k h k denotes the space of compact operators between arbitrary complex hilbert spaces h and k then every surjective isometry f s k h k s k h k admits an extension to a surjective real linear isometry t k h k k h k

a perturbation boundary element code for steady state groundwater flow in heterogeneous aquifers a boundary element code is developed for the steady state darcy s flow in heterogeneous porous media the solution is based on the expansion of the piezometric head into perturbation series the governing equation is decomposed into a laplace equation and a sequence of poisson equations with known right hand sides regular boundary element procedure is applied for their solutions three numerical examples with moderate hydraulic conductivity variations are provided to demonstrate the applicability of the code the convergence of the perturbation solution is discussed using a one dimensional problem

relatively weakly open sets in closed balls of banach spaces and real jb triples of finite rank we prove that given a real jb triple x there exists a nonempty relatively weakly open subset of the closed unit ball of x with diameter less than 2 if and only if the banach space of x is isomorphic to a hilbert space moreover we give the structure of real jb triples whose banach spaces are isomorphic to hilbert spaces such real jb triples are also characterized in two different purely algebraic ways

the daugavet property of c algebras jb triples and of their isometric preduals a banach space x is said to have the daugavet property if every rank one operator t x x satisfies id t 1 t we give geometric characterizations of this property in the settings of c algebras jb triples and their isometric preduals we also show that in these settings the daugavet property passes to ultrapowers and thus it is equivalent to an stronger property called the uniform daugavet property

boundedness of completely additive measures with application to 2 local triple derivations we prove a jordan version of dorofeev s boundedness theorem for completely additive measures and use it to show that every not necessarily linear nor continuous 2 local triple derivation on a continuous jbw triple is a triple derivation 2 local triple derivations are well understood on von neumann algebras jbw triples which are properly defined in section i are intimately related to infinite dimensional holomorphy and include von neumann algebras as special cases in particular continuous jbw triples can be realized as subspaces of continuous von neumann algebras which are stable for the triple product xy z zy x and closed in the weak operator topology

aron berner extensions of triple maps with application to the bidual of jordan banach triple systems abstract by extending the notion of arens regularity of bilinear mappings we say that a bounded trilinear map on the cartesian product of banach spaces is aron berner regular when all its six aron berner extensions to the cartesian product of the bidual spaces coincide we give some results on the aron berner regularity of certain trilinear maps we then focus on the bidual e of a jordan banach triple system e and investigate those conditions under which e is itself a jordan banach triple system under each of the aron berner extensions of the triple product we also compare these six triple products with those arising from certain ultrafilters based on the ultrapower formulation of the principle of local reflexivity in particular we examine the aron berner triple products on the bidual of a jb triple in relation with the so called dineen s theorem some illuminating examples are included and some questions are also left undecided

jordan structures in harmonic functions and fourier algebras on homogeneous spaces we study the jordan structures and geometry of bounded matrix valued harmonic functions on a homogeneous space and their analogue the harmonic functionals in the setting of fourier algebras of homogeneous spaces

the range of a structural projection abstract let a be a jbw triple a linear subspace j of a is called an inner ideal in a provided that the subspace j a j is contained in j a subtriple b in a is said to be complemented if a b ker b where ker b a a b a b 0 a complemented subtriple in a is a weak closed inner ideal a linear projection on a is said to be structural if for all elements a b and c in a formula the range of a structural projection is a complemented subtriple and conversely a complemented subtriple is the range of a unique structural projection we analyze the structure of the weak closed inner ideal generated by two arbitrary tripotents in a jbw triple in terms of the simultaneous peirce spaces of three suitably chosen pairwise compatible tripotents this result is then used to show that every weak closed inner ideal j in a jbw triple a is a complemented subtriple in a and therefore the range of a unique structural projection on a as an application structural projections on w algebras are considered

unit free contractive projection theorems for c jb and jb algebras abstract we prove that if a is a possibly non unital non commutative j b algebra and if a a is a positive contractive linear projection then a endowed with the product x y x y becomes naturally a non commutative j b algebra and moreover the equality a b a b holds for all a b a the appropriate variant of this result with jb algebra instead of non commutative j b algebra is also obtained in the non commutative j b case the requirement of positiveness for can be relaxed to the one that the equality holds in general this relaxing is strict but it is not strict if is bicontractive actually positive bicontractive linear projections on non commutative j b algebras are fully described and a structure theorem for bicontractive linear projections without any extra requirement on non commutative j b w algebras is proved finally bicontractive linear projections on c algebras are studied in detail

distortion of locally biholomorphic bloch mappings on bounded symmetric domains abstract we generalize bonk s distortion theorem on the unit disc in the complex plane to locally biholomorphic mappings on finite dimensional bounded symmetric domains as an application we obtain a lower bound for the bloch constant for various classes of locally biholomorphic bloch mappings

superlinear problems without ambrosetti and rabinowitz growth condition superlinear elliptic boundary value problems without ambrosetti and rabinowitz growth condition are considered existence of nontrivial solution result is established by combining some arguments used by struwe and tarantello and schechter and zou also by wang and wei firstly by using the mountain pass theorem due to ambrosetti and rabinowitz is constructed a solution for almost every parameter by varying the parameter then it is considered the continuation of the solutions

boundary element solution for stochastic groundwater flow temporal weakly stationary problems this paper continues the development of boundary integral equation technique for solving stochastic groundwater flow problems the case of aquifers under deterministic hydraulic conductivity but subject to random boundary condition and domain recharge has been investigated in an earlier paper under the assumption of steady state governing equation in the current paper the governing equation is transient but the temporal variation of second order statistical moments is assumed to be weakly stationary several examples of fundamental importance to the understanding of stochastic process are examined both by the analytical and by the numerical boundary element techniques

generalised f algebras as predual algebras of jbw triples and characterisations of the fourier algebras on locally compact groups abstract we introduce the notion of a generalised f algebra as a banach algebra a whose banach space dual is a j b w triple with a certain additional condition on a distinguished character of a this generalises the well known notion of f algebras which in turn includes as special cases many important classes of banach algebras on locally compact groups and semigroups our main use of this new notion is to give some axiomatic characterisations of the fourier algebras on locally compact groups strengthening our previous work 37 but we also quickly review some well known results in f algebras that can be extended to the context of generalised f algebras

banach space characterizations of unitaries a survey abstract we survey banach space characterizations of unitary elements of c algebras jb triples and jb algebras in the case of the existence of a pre dual appropriate specializations of these characterizations are also reviewed

central kernels of subspaces of jb triples abstract an investigation of the norm central kernel k n l of an arbitrary norm closed subspace l of a jb triple and the central kernel k l of a weak closed subspace l of a jbw triple is carried out it is shown that these geometrically defined objects have purely algebraic characterizations the results providing new information about c algebras and w algebras

on grassmannians associated with jb triples then is a complex lie group that has precisely n 1 orbits e0 en in e each er is the locally closed complex submanifold of all matrices of rank r clearly er 1 is in the closure of er for every 1 r n and en is the unique open orbit for every pair of integers p q 0 let gp q be the grassmannian of all p planes in cp q then gp q is a compact symmetric hermitian manifold of dimension pq holomorphically equivalent to gq p every er is in a canonical way a equivariant holomorphic fibre bundle

a priori estimates and existence for elliptic systems via bootstrap in weighted lebesgue spaces we present a new general method to obtain regularity and a priori estimates for solutions of semilinear elliptic systems in bounded domains this method is based on a bootstrap procedure used alternatively on each component in the scale of weighted lebesgue spaces lp lp x dx where x is the distance to the boundary using this method we significantly improve the known existence results for various classes of elliptic systems

boundary integral equation solutions to moving interface between two fluids in porous media the boundary integral equation method is formulated for and applied to problems concerning a moving interface between two fluids in porous media the mixing between two fluids is assumed to be insignificant a sharp interface exists between them numerical and experimental results are presented for the tilting of a vertical interface in a hele shaw cell during the initial stage of the interfacial movement nonlinear effects are clearly demonstrated the biem results are also compared to experimental results for a transient salt water intrusion problem

existence of a positive solution and numerical solution for some elliptic superlinear problem abstract in this paper we prove the existence of positive solutions of an elliptic superlinear problem also we are interested here in getting results concerning the existence of positive solutions for the discrete formulation of our problem therefore in order to do it we employ the radial solutions of the elliptic superlinear problem obtaining a second order dynamic equation on time scales which encompasses discrete continuous and hybrid formulations of our problem this unified equation allows us to present numerical simulations which give us a more precise analysis and description concerning the behavior of the solution according to the parameters

on the extension of isometries between the unit spheres of von neumann algebras abstract we prove that every surjective isometry between the unit spheres of two von neumann algebras admits a unique extension to a surjective real linear isometry between these two algebras

multilayered leaky aquifer systems 1 pumping well solutions this paper presents an analytical solution of a radial flow to a pumping well at constant discharge located in a multilayered leaky aquifer system the aquifer system is composed of alternating layer of aquifers and aquitards and is modeled after the theory of neuman witherspoon and herrera the resulting coupled integrodifferential equation system is handled by the laplace transform technique which removes not only the time variable but also the convolutional integral green s functions for the coupled elliptic partial differential equations are then sought utilizing a numerical laplace inversion algorithm the drawdown at any given time and location in any layer can be evaluated several examples are given for validation and exploration purposes

isometries of non self adjoint operator algebras abstract we study isometries of certain non self adjoint operator algebras by means of the structure of the complete holomorphic vector fields on their unit balls and the associated partial jordan triple products we show that isometries of nest sub algebras of b h are of the form t utw or t ujt jw where u w are suitable unitary operators and j a fixed involution of h

horoballs and iteration of holomorphic maps on bounded symmetric domains abstract given a fixed point free compact holomorphic self map f on a bounded symmetric domain d which may be infinite dimensional we establish the existence of a family h 0 of convex f invariant domains at a point in the boundary d of d which generalises completely wolff s theorem for the open unit disc in c further we construct horoballs at and show that they are exactly the f invariant domains when d is of finite rank consequently we show in the latter case that the limit functions of the iterates f n with weakly closed range all accumulate in one single boundary component of d

on superlinear problems without the ambrosetti and rabinowitz condition abstract existence and multiplicity results are obtained for superlinear p laplacian equations without the ambrosetti and rabinowitz condition to overcome the difficulty that the palais smale sequences of the euler lagrange functional may be unbounded we consider the cerami sequences our results extend the recent results of miyagaki and souto o miyagaki m souto superlinear problems without ambrosetti and rabinowitz growth condition j differential equations 245 2008 3628 3638

measures of weak non compactness in preduals of von neumann algebras and jbw triples abstract we prove among other results that three standard measures of weak non compactness coincide in preduals of jbw triples this result is new even for preduals of von neumann algebras we further provide a characterization of jbw triples with strongly wcg predual and describe the order of seminorms defining the strong topology as a byproduct we improve a characterization of weakly compact subsets of a jbw triple predual providing so a proof for a conjecture open for almost eighteen years on weakly compact operators from a jb triple into a complex banach space

the alternative dunford pettis property on projective tensor products a banach space x has the dunford pettis property dpp if and only if whenever xn and pn are weakly null sequences in x and x respectively we have pn xn 0 freedman introduced a stricly weaker version of the dpp called the alternative dunford pettis property dp1 a banach space x has the dp1 if whenever xn x weakly in x with kxnk kxk and xn is weakly null in x we have that xn xn 0 the authors study the dp1 on projective tensor products of c algebras and jb triples their main result theorem 3 5 states that if x and y are banach spaces such that x contains an isometric copy of c0 and y contains an isometric copy of c 0 1 then x y the projective tensor product of x and y does not have the dp1 as a corollary they get that if x and y are jb triples such that x is not reflexive and y contains 1 then x y does not have the dp1 furthermore if a and b are infinite dimensional c algebras then a b has the dpp if and only if a b has the dp1 if and only if both a and b have the dpp and do not contain 1

basic qualitative and quantitative results for solutions to nonlinear dynamic equations on time scales with an application to economic modelling abstract this article investigates both basic qualitative and basic quantitative properties of solutions to first and higher order dynamic equations on time scales and thus provides a foundation and framework for future advanced nonlinear studies in the field particular focus lies in the existence uniqueness dependency approximation and explicit representation of solutions to nonlinear initial value problems the main tools used are from modern areas of nonlinear analysis including the fixed point theorems of banach and schafer the method of successive approximations a novel definition of measuring distance in metric spaces and normed spaces and a separation of variables technique is introduced to the general time scale setting the new results compliment and extend those of stefan hilger s seminal paper of 1990 as an application of the new results we present and analyse a simple model from economics known as the keynesian cross model with lagged income in the general time scale environment ideas suggesting further applications and possible new directions for the novel results are also presented

2 local triple homomorphisms on von neumann algebras and jbw triples abstract we prove that every not necessarily linear nor continuous 2 local triple homomorphism from a jbw triple into a jb triple is linear and a triple homomorphism consequently every 2 local triple homomorphism from a von neumann algebra respectively from a jbw algebra into a c algebra respectively into a jb algebra is linear and a triple homomorphism

a technique in using integrodifferential equations for model simulation of multiaquifer systems a numerical technique for modeling a multiaquifer system is developed on the basis of a quasi three dimensional flow model the model consists of many horizontal aquifers interconnected by leakage flux from aquitards the direct flow across aquitards and yield from aquitard storage are taken into account in leakage flux terms in the form of convolution integrals mathematical formulation results in flow functions which diminish with time and can be approximated by few exponential terms they have been proved to be very convenient in a numerical solution scheme involving the convolution integrals the approach reduces the dimensionality of the problem and uncouples the equations corresponding to each of the aquifers the technique is flexible and can be used for any basin geometry with an arbitrary pumping scheme the validity of the technique is demonstrated by comparing the model results with available analytical solutions in general it appears that this technique is more economical than the full three dimensional model or even the quasi three dimensional models that use one dimensional elements to represent the aquitards

darcy s flow with variable permeability a boundary integral solution a boundary integral equation method biem for darcy s flow with spatially varied permeability is developed the formulation requires that green s function be found for each given permeability variation for a few permeability functions in one and two dimensions which can be used to fit field permeability data closed form green s functions are obtained numerical examples are solved and verified

on the structure of c0 semigroups of holomorphic caratheodory isometries in hilbert space abstract we establish closed formulas for all strongly continuous one parameter semigroups of holomorphic caratheodory isometries of the unit ball of a hilbert space in terms of spectral resolutions of skew self adjoint dilations related to the reich shoikhet nonlinear infinitesimal generator

iteration of holomorphic maps on lie balls abstract we investigate iterations of fixed point free holomorphic self maps on a lie ball of any dimension where a lie ball is a bounded symmetric domain and the open unit ball of a spin factor which can be infinite dimensional we describe the invariant domains of a holomorphic self map f on a lie ball d when f is fixed point free and compact and show that each limit function of the iterates f n has values in a one dimensional disc on the boundary of d we show that the mobius transformation g a induced by a nonzero element a in d may fail the denjoy wolff type theorem even in finite dimension we determine those which satisfy the theorem