multiple symmetric positive solutions to a new kind of four point boundary value problem abstract in this paper we are concerned with the existence of multiple symmetric positive solutions for four point boundary value problems with one dimensional p laplacian p x t h t f t x t x t 0 0 t 1 subject to one of the following boundary conditions x 0 x 0 x 1 x 0 or x 0 g x 0 x 1 g x 0 where p s s p 2 s p 1 0 1 1 by using a fixed point theorem due to avery and peterson we provide sufficient conditions for the existence of at least three positive solutions the interesting points here are that and the nonlinear term f are involved with the first order derivative explicitly

twin positive solutions for higher order m point boundary value problems with sign changing nonlinearities a new fixed point theorem on double cones is applied to obtain the existence of at least two positive solutions for the 2nd order m point boundary value problemy 2 n t f t y t y t y 2 n 1 t 0

an unsplit higher order godunov method for scalar conservation laws in multiple dimensions abstract in this paper we develop an unsplit higher order godunov method for scalar conservation laws in two dimensions the method represents an extension for the special case being considered of methods developed by colella and by van leer in our method we begin with a piecewise bilinear representation of the solution on each grid cell a new piecewise bilinear representation at the next time level is then obtained from a two step procedure in the first step a conservative predictor corrector scheme derived from the integral form of the differential equation and characteristic considerations is used to obtain average values of the solution over grid cells at the new time level next these new average values are then used to construct a limited piecewise bilinear profile for each cell at the new time level the resulting method is shown to satisfy a maximum principle for constant coefficient linear advection computational results are presented comparing the new method to colella s method for linear advection the method is also applied to two model problems from porous media flow miscible and immiscible displacement the new scheme provides accurate resolution of sharp fronts without any significant distortion

multiple positive solutions for multipoint boundary value problems with one dimensional p laplacian abstract in this paper we consider the multiplicity of positive solutions for the one dimensional p laplacian differential equation p u q t f t u u 0 t 0 1 subject to some boundary conditions by means of a fixed point theorem due to avery and peterson we provide sufficient conditions for the existence of multiple positive solutions to some multipoint boundary value problems

a multi point boundary value problem with two critical conditions abstract we apply a coincidence degree theorem due to mawhin to show the existence of at least one solution of the nonlinear second order multi point boundary value problem u t f t u t u t t 0 1 u 0 u i 1 n i u i u 1 where 0 1 0 i 1 i 1 n i 1 n i i 1 n i i 1 n 2 and f 0 1 r 2 r satisfying the caratheodory conditions in our setting both boundary conditions are responsible for resonance

characteristic based rotated upwind scheme for the euler equations a rotated upwind scheme is developed that calculates shock waves oblique to the grid with nearly the same resolution as shocks that are aligned with the grid the scheme applies flux difference splitting along two orthogonal directions for each cell face with the directions computed on the basis of pressure gradient data rotated extrapolations and flux limiting are used to generate second order spatial accuracy a filtering of the pressure gradient data allows the convergence of the rotated scheme with continuously updated upwinding angles at a rate comparable to classical schemes flux evaluations based on characteristi c variables and characteristic boundary conditions are discussed and implemented the method has been tested on two simple shock reflection problems and formally second order results capture the oblique shocks with only two to three cells in the shock transition region

numerical methods for fourth order elliptic equations with nonlocal boundary conditions this paper is concerned with some numerical methods for a fourth order semilinear elliptic boundary value problem with nonlocal boundary condition the fourth order equation is formulated as a coupled system of two second order equations which are discretized by the finite difference method three monotone iterative schemes are presented for the coupled finite difference system using either an upper solution or a lower solution as the initial iteration these sequences of monotone iterations called maximal sequence and minimal sequence respectively yield not only useful computational algorithms but also the existence of a maximal solution and a minimal solution of the finite difference system also given is a sufficient condition for the uniqueness of the solution this uniqueness property and the monotone convergence of the maximal and minimal sequences lead to a reliable and easy to use error estimate for the computed solution moreover the monotone convergence property of the maximal and minimal sequences is used to show the convergence of the maximal and minimal finite difference solutions to the corresponding maximal and minimal solutions of the original continuous system as the mesh size tends to zero three numerical examples with different types of nonlinear reaction functions are given in each example the true continuous solution is constructed and is used to compare with the computed solution to demonstrate the accuracy and reliability of the monotone iterative schemes

use of a rotated riemann solver for the two dimensional euler equations a scheme for the two dimensional euler equations that uses flow parameters to determine the direction for upwind differencing is described this approach respects the multi dimensional nature of the equations and reduces the grid dependence of conventional schemes several angles are tested as the dominant upwinding direction including the local flow and velocity magnitude gradient angles roe s approximate riemann solver is used to calculate fluxes in the upwind direction as well as for the flux components normal to the upwinding direction the approach is first tested for two dimensional scalar convection where the scheme is shown to have accuracy comparable to a high order muscl scheme solutions of the euler equations are calculated for a variety of test cases substantial improvement in the resolution of shock and shear waves is realized the approach is promising in that it uses flow solution features rather than grid features to determine the orientation for the solution method

a fourth order compact finite difference method for nonlinear higher order multi point boundary value problems a fourth order compact finite difference method is proposed for a class of nonlinear 2nth order multi point boundary value problems the multi point boundary condition under consideration includes various commonly discussed boundary conditions such as the three or four point boundary condition n 2 point boundary condition and 2 n m point boundary condition the existence and uniqueness of the finite difference solution are investigated by the method of upper and lower solutions without any monotone requirement on the nonlinear term the convergence and the fourth order accuracy of the method are proved an efficient monotone iterative algorithm is developed for solving the resulting nonlinear finite difference systems various sufficient conditions for the construction of upper and lower solutions are obtained some applications and numerical results are given to demonstrate the high efficiency and advantages of this new approach

existence of multiple positive solutions for nonlinear m point boundary value problems in this paper we afford some sufficient conditions to guarantee the existence of multiple positive solutions for the nonlinear m point boundary value problem for the one dimensional p laplacian f p u f t u 0 t 0 1 u 0 i 1m 2b iu x i u 1 i 1m 2a iu x i

positive solutions to a new kind sturm liouville like four point boundary value problem abstract in this paper we considered the following four point boundary value problem x t h t f t x t x t 0 0 t 1 x 0 1 x 0 x 1 2 x 0 where 0 1 1 0 2 1 1 0 1 1 2 1 2 1 2 0 by applying fixed point theorems we obtain a variety of existence results in particular our four point boundary condition is a new kind sturm liouville like boundary condition which has rarely been considered up to now

positive solutions of nonlinear second order m point boundary value problem abstract in this paper by using krasnoselskii s fixed point theorem of cone expansion compression type and under suitable conditions we present the existence of single and multiple positive solutions to the nonlinear second order m point boundary value problem u t a t f u t 0 0 t 1 u 0 0 u 1 i 1 m 2 a i u i where is a positive parameter a i 0 for i 1 2 m 3 and a m 2 0 i satisfy 0 1 2 m 2 1 and i 1 m 2 a i i 1 we derive an explicit interval of such that for any in this interval the existence of at least one positive solution to the boundary value problem is guaranteed and the existence of at least two solutions for in an appropriate interval is also discussed

multidimensional upwind methods for hyperbolic conservation laws abstract we present a class of second order conservative finite difference algorithms for solving numerically time dependent problems for hyperbolic conservation laws in several space variables these methods are upwind and multidimensional in that the numerical fluxes are obtained by solving the characteristic form of the full multidimensional equations at the zone edge and that all fluxes are evaluated and differenced at the same time in particular operator splitting is not used correct behavior at discontinuities is obtained by the use of solutions to the riemann problem and by limiting some of the second order terms numerical results are presented which show that the methods described here yield the same high resolution as the corresponding operator split methods

multiple positive solutions for nth order m point boundary value problems with all derivatives abstract we investigate the existence of positive solutions for the boundary value problem u n t f t u t u t u n 2 t u n 1 t 0 0 t 1 u 0 u 0 u n 2 0 0 u n 1 1 i 1 m 2 k i u n 1 i where f 0 1 r n r is continuous k i 0 i 1 2 m 2 0 i 1 m 2 k i 1 we give at first the associated green s function and some of its properties then imposing growth conditions on f we obtain the existence of at least three positive solutions for the boundary value problem by using the five functional fixed point theorem finally we give an example to demonstrate our result

existence results for n point boundary value problem of second order ordinary differential equations abstract this study concerns the existence of positive solutions to the boundary value problem u a t f u 0 t 0 1 u 0 i 1 n 2 b i u i u 1 i 1 n 2 a i u i where i 0 1 with 0 1 2 n 2 1 a i b i 0 with 0 i 1 n 2 a i 1 and i 1 n 2 b i 1 by applying the krasnoselskii s fixed point theorem in banach spaces some sufficient conditions guaranteeing the existence of at least one positive solution or at least two positive solutions are established for the above general n point boundary value problem

a two dimensional version of the godunov scheme for scalar balance laws a godunov scheme is derived for two dimensional scalar conservation laws without or with source terms following ideas originally proposed by boukadida and leroux math comput 63 1994 pp 541 553 in the context of a staggered lax friedrichs scheme in both situations the numerical fluxes are obtained at each interface of a uniform cartesian computational grid just by means of the external waves involved in the entropy solution of the elementary two dimensional 2d riemann problems in particular all the wave interaction phenomena are overlooked this restriction of the wave pattern suffices for deriving the exact numerical fluxes of the staggered lax friedrichs scheme but it furnishes only an approximation for the godunov scheme we show that under convenient assumptions these flux functions are smooth and the resulting discretization process is stable under nearly optimal cfl restriction a well balanced extension is presented relying on the curl free component of the helmholtz decomposi

solvability of the φ laplacian with nonlocal boundary conditions rather mild sufficient conditions are provided for the existence of positive solutions of a boundary value problem of the form f x t c t fx t 0 email protected 0 1 x 0 l 0 x x 1 l 1 x 0 which unify several cases discussed in the literature in order to formulate these conditions one needs to know only properties of the homeomorphism f r r and have information about the level of growth of the response operator f no metric information concerning the linear operators l 0 l 1 in the boundary conditions is used except that they are positive and continuous and such that l j 1 email protected 0 1

positive solution of singular higher order m point boundary value problem with nonlinearity that changes sign this paper is about a class of singular higher order m point boundary value problems with nonlinearity that changes sign using the fixed point index theory we get a sufficient condition for the existence of positive solution to this problem

parallel equalization structure for mimo fbmc oqam systems under strong time and frequency selectivity offset qam based filterbank multicarrier fbmc oqam has been shown to be a promising alternative to cyclic prefix orthogonal frequency division multiplexing for the future generation of wireless communication systems unfortunately as the channel gets more selective in time and frequency the fbmc oqam orthogonality is progressively destroyed and distortion appears after the demodulation process at the receiver while channel frequency selectivity has been very widely studied in the fbmc literature the impact of time selectivity of the channel has not received that much attention in this paper the effect of the two types of selectivity on a multiple input multiple output mimo fbmc system is characterized and a parallel equalization structure that can compensate for the doubly dispersive nature of the channel is proposed this design uses multiple analysis filterbanks and extends previous approaches that were dealing only with channel frequency selectivity a theoretical approximation of the remaining distortion after equalization is given the study is performed for a general mimo system but can also be particularized to single input single output systems simulation results demonstrate the high efficiency of the proposed receiver structure and the accuracy of the theoretical approximations is verified

multiple positive solutions of multi point boundary value problem for second order impulsive differential equations this paper is devoted to study the existence of multiple positive solutions for the second order multi point boundary value problem with impulse effects the arguments are based upon fixed point theorems in a cone an example is worked out to demonstrate the main results

existence and iteration of monotone positive solutions for multipoint boundary value problem with p laplacian operator in the paper we obtain the existence of monotone positive solutions and establish acorresponding iterative scheme for the following multipoint boundary value problem with p laplacian operator f p u t q t f t u t 0 0

three point boundary value problems for difference equations in this paper the existence and nonexistence of positive solutions for three point nonlinear boundary value problems of difference equations are considered

existence of solutions of boundary value problems for second order functional differential equations abstract in this paper we deal with the boundary value problem x f t x x t x x t x 0 x 0 c 1 c 2 c 1 c 2 r x j 0 x 1 x j 0 where f car j r c r r c r c r j 0 1 1 a j a 0 1 a j and a 0 1 are two special sets of functionals and x j is the restriction of x to j we find sufficient conditions for the existence of solutions of the above problem the proof is based on the leray schauder degree theory

existence and iteration of positive solutions for a multipoint one dimensional p laplacian boundary value problem abstract in this paper we study the existence and iteration of positive solutions for the one dimensional p laplacian differential equation p u t q t f t u t u t 0 t 0 1 subject to the following multipoint boundary condition u 0 i 1 n 2 i u i u 1 i 1 n 2 i u i by applying a monotone iterative method we not only obtain the existence of positive solutions for the problem but also establish iterative schemes for approximating the solutions

on existence and multiplicity of positive solutions to singular multi point boundary value problems the existence and multiplicity of positive solutions are established for the multi point boundary value problem p t u t f t u t 0 0 t 1 u 0 j 1maju xj w 1 j 1mbjw xj where w t p t u t aj bj 0 with 0 j 1maj 1 and j 1mbj 1 xj 0 1 with 0 x1 x2 xm 1 under certain conditions on p and f the arguments are based upon the positivity of the green s function and the krasnosel skii fixed point theorem

existence of triple positive solutions for multi point boundary value problems with a one dimensional p laplacian in this paper we consider the existence of multiple positive solutions for multi point boundary value problems with a one dimensional p laplacian f p u t q t f t u t u t 0 01 a email protected email protected i email protected email protected m 2 0 i 1 m email protected i i 1 m email protected email protected 0 1 0 x 1 x 2 x m 2 1 by the fixed point theorem due to avery and peterson we provide sufficient conditions for the existence of multiple positive solutions to the above boundary value problem

positive solutions for multipoint boundary value problems with a one dimensional p laplacian abstract in this paper we consider the multipoint boundary value problem for a one dimensional p laplacian p u f t u 0 t 0 1 subject to the boundary value condition u 0 i 1 n 2 i u i u 1 i 1 n 2 i u i where p s s p 2 s p 1 i 0 1 with 0 1 2 n 2 1 and i i satisfy i i 0 0 i 1 n 2 i 1 and i 1 n 2 i 1 using a fixed point theorem for operators on a cone we provide sufficient conditions for the existence of multiple positive solutions to the above boundary value problem

analysis and design of ofdm oqam systems based on filterbank theory a discrete time analysis of the orthogonal frequency division multiplex offset qam ofdm oqam multicarrier modulation technique leading to a modulated transmultiplexer is presented the conditions of discrete orthogonality are established with respect to the polyphase components of the ofdm oqam prototype filter which is assumed to be symmetrical and with arbitrary length fast implementation schemes of the ofdm oqam modulator and demodulator are provided which are based on the inverse fast fourier transform non orthogonal prototypes create intersymbol and interchannel interferences isi and ici that in the case of a distortion free transmission are expressed by a closed form expression a large set of design examples is presented for ofdm oqam systems with the number of subcarriers going from four up to 2048 which also allows a comparison between different approaches to get well localized prototypes

positive solutions of m point boundary value problems for higher order ordinary differential equations abstract in this paper we study m point boundary value problems for higher order ordinary differential equation y 2 n t f t y t y t y 2 n 1 t 0 t 1 y 2 i 0 0 y 2 i 1 j 1 m 2 k i j y 2 i j 0 i n 1 where f is allowed to change sign and 0 0 1 2 m 2 m 1 1 we show sufficient conditions for the existence of at least two positive solutions by applying a new fixed point theorem in cones and the associated green s function in particular the second positive solutions for the above problem is not concave

on numerical studies of multi point boundary value problem and its fold bifurcation based upon shooting method we set up a numerical method for approximating solutions and fold bifurcation solutions of second order multi point boundary value problems we prove the equivalence of the regularity of solutions and simple fold bifurcation solutions between the numerical method and the multi point boundary value problems many numerical experiments are carried out to illustrate the theoretical analysis from which we explore that the fold bifurcation phenomenon are generic in multi point boundary value problems although there is no theoretical analysis in the literature so far

successive iteration and positive symmetric solution for a sturm liouville like four point boundary value problem with a p laplacian operator abstract in this paper we consider the following sturm liouville like four point p laplacian boundary value problem with the nonlinear term f depending on the first order derivative p u t q t f t u t u t 0 0 t 1 subject to the boundary conditions u 0 u 0 u 1 u 0 by using a monotone iterative technique the existence of symmetric positive solutions and corresponding iterative schemes are obtained

extension of the piecewise parabolic method to multidimensional ideal magnetohydrodynamics an extension of the piecewise parabolic method to treat multidimensional ideal magnetohydrodynamical equations is presented in this paper the multidimensional scheme is constructed from a one dimensional functioning code based on the dimensional splitting method originally suggested by strang the functioning code is built upon a nonlinear riemann solver for ideal mhd equations recently developed by the authors the correctness of the scheme is tested in the steepening of waves in both one and two dimensional situations and in various mhd shock tube problems which involve all the discontinuities in ideal mhd the robust character of the scheme is demonstrated in the shock tube problems and in the interaction between mhd shocks and a cloud the results of these problems show that the scheme keeps the principal advantages of a high order godunov scheme robust operation in the presence of very strong waves thin shock fronts with little attendant noise generation and thin contact discontinuity

positive solutions for some second order four point boundary value problems abstract in this paper the second order four point boundary value problem x t h t f t x t 0 0 t 1 x 0 a x x 1 b x is studied where 0 1 0 a b 1 and h 0 1 0 f 0 1 0 0 are nonnegative continuous functions by the use of the property of the corresponding green s function fixed point index theory leray schauder degree and upper and lower solution method some existence nonexistence and multiplicity results of positive solutions are acquired

parallelized structures for mimo fbmc under strong channel frequency selectivity a novel architecture for mimo transmission and reception of filterbank multicarrier fbmc modulated signals under strong frequency selectivity is presented the proposed system seeks to approximate an ideal frequency selective precoder and linear receiver by taylor expansion exploiting the structure of the analysis and synthesis filterbanks the resulting architecture is implemented by linearly combining conventional mimo linear transceivers which are applied to sequential derivatives of the original filterbank the classical per subcarrier precoding linear receiver configuration is obtained as a special case of this architecture when only one stage is fixed at both transmitter and receiver an asymptotic expression for the resulting intersymbol intercarrier isi ici distortion is derived assuming that the number of subcarriers grows large this expression can in practice be used in order to determine the number of parallel stages that need to be implemented in the proposed architecture performance evaluation studies confirm the substantial advantage of the proposed scheme in practical frequency selective mimo scenarios

existence of positive solution for singular semi positone k n k conjugate m point boundary value problem this paper is about a class of singular semi positone k n k conjugate m point boundary value problems by using the fixed point index theory we get a sufficient condition for the existence of positive solution to this problem

three positive solutions for higher order m point boundary value problems abstract in this paper we consider the existence of at least three positive solutions for the 2nth order m point boundary value problem y 2n t f t y t y t y 2 n 1 t 0 t 1 y 2i 0 0 y 2i 1 j 1 m 2 k ij y 2i j 0 i n 1 where kij 0 i 0 1 n 1 j 1 2 m 2 0

positive solutions of a general discrete boundary value problem in this paper the existence of positive solutions for a nonlinear general discrete boundary value problem is established such results extend and improve some known facts for the two point and three point boundary value problems particularly the boundary value conditions can be nonlinear and the method is new for explaining the main results some numerical examples are also given

existence and multiplicity of solutions for four point boundary value problems at resonance abstract this paper deals with the second order four point boundary value problem x t f t x t 0 t 1 x 0 ax x 1 bx where f 0 1 r r is continuous 0 1 0 a 1 1 0 b 1 a 1 b 1 a s 1 b 0 by using the coincidence degree theory the method of lower and upper solutions is established as applications some existence and multiplicity results are obtained

an approximate two dimensional riemann solver for hyperbolic systems of conservation laws a two dimensional riemann solver is proposed for the solution of hyperbolic systems of conservation laws in two dimensions of space the solver approximates the solution of a so called angular two dimensional riemann problem as the weighted sum of the solutions of one dimensional riemann problems the weights are proportional to the aperture of the regions of constant state the two dimensional solver is used to determine the solution of the equations at the cell vertices the intercell fluxes are estimated using a linear combination between the point solutions at the cell vertices and the solutions of the one dimensional problems at the centers of the cell interfaces besides allowing the computational time step to be increased the method gives more accurate results and is less sensitive to the anisotropy induced by the computational grid

positive solutions for second order m point boundary value problems by using the schauder fixed point theorem and analysis method we establish the existence of solutions for the m point boundary value problem u t a t f u 0 u 0 0 u 1 i 1m 2kiu i b where b ki 0 i 1 2 m 2 0 b

an unsplit 3d upwind method for hyperbolic conservation laws abstract an unsplit upwind method for solving hyperbolic conservation laws in three dimensions is developed this paper derives the algorithm by generalizing a two dimensional advection algorithm of van leer and colella to three dimensions and then making appropriate modifications the method is implemented using the equations of gas dynamics several test problems are computed to both verify and display the behavior of the method these test problems include a 1d blast wave a 2d shock reflection off a 30 ramp and a 3d astrophysical jet

existence of positive solutions to n point nonhomogeneous boundary value problem in this paper we are concerned with the existence of positive solutions to a n point nonhomogeneous boundary value problem by using the krasnoselskii s fixed point theorem in banach spaces some sufficient conditions guaranteeing the existence of positive solution is established for the n point nonhomogeneous boundary value problem

solvability of an m point boundary value problem for second order ordinary differential equations let 0 1 r2 r be a function satisfying caratheodory s conditions and e t l1 0 1 let i 0 1 ai r all of the ai s having the same sign i 1 2 m 2 0 1 2 m 2 1 be given this paper is concerned with the problem of existence of a solution for the m point boundary value problem x t t x t x t e t t 0 1 e formula conditions for the existence of a solution for the above boundary value problem are given using the leray schauder continuation theorem

multiple positive solutions for second order m point boundary value problems abstract in this paper the second order m point boundary value problem u t f t u 0 0 t 1 u 0 0 u 1 i 1 m 2 k i u i 0 is studied where k i 0 i 1 2 m 2 0 1 2 m 2 1 we give at first the associated green s function and its properties for the m point boundary value problem and growth conditions are imposed on f which yield the existence of at least three positive solutions by using the five functionals fixed point theorem and the properties

existence of multiple positive solutions for one dimensional p laplacian abstract in this paper we consider the multipoint boundary value problem for one dimensional p laplacian p u f t u 0 t 0 1 subject to the boundary value conditions p u 0 i 1 n 2 a i p u i u 1 i 1 n 2 b i u i where p s s p 2 s p 1 i 0 1 with 0 1 2 n 2 1 and a i b i satisfy a i b i 0 0 i 1 n 2 a i 1 and i 1 n 2 b i 1 using a fixed point theorem for operators on a cone we provide sufficient conditions for the existence of multiple at least three positive solutions to the above boundary value problem

positive solutions of three point boundary value problems for systems of nonlinear second order ordinary differential equations abstract in this paper we study the three point boundary value problems for systems of nonlinear second order ordinary differential equations of the form u f t v t 0 1 v g t u t 0 1 u 0 v 0 0 u u 1 v v 1 under some conditions we show the existence and multiplicity of positive solutions of the above problem by applying the fixed point index theory in cones

the iterative solutions of 2nth order nonlinear multi point boundary value problems abstract the aim of this paper is to investigate the existence of iterative solutions for a class of 2 n th order nonlinear multi point boundary value problems the multi point boundary condition under consideration includes various commonly discussed boundary conditions such as three or four point boundary condition n 2 point boundary condition and 2 n m point boundary condition the existence problem is based on the method of upper and lower solutions and its associated monotone iterative technique a monotone iteration is developed so that the iterative sequence converges monotonically to a maximal solution or a minimal solution depending on whether the initial iteration is an upper solution or a lower solution two examples are presented to illustrate the results

existence of multiple positive solutions for multipoint boundary value problems with a one dimensional p laplacian abstract in this paper we consider the multipoint boundary value problem for a one dimensional p laplacian p u a t f t u 0 t 0 1 u 0 0 u 1 i 1 m 2 a i u i where p s s p 2 s p 1 0 1 2 m 2 1 a i 0 for i 1 2 m 3 and a m 2 0 using a fixed point theorem for operators on a cone we provide sufficient conditions for the existence of multiple positive solutions to the above boundary value problem

necessary and sufficient conditions for the existence of solution to three point bvp abstract we study the existence of a solution of the three point boundary value problem p x x g x h x 0 0 x x we give sufficient and necessary conditions on g and h in order for p to have a real solution our conditions are of landesman lazer type and depend on the real values of and

on an m point boundary value problem for second order ordinary differential equations where q e 0 1 is given we obtain conditions for the existence and uniqueness of a solution for the boundary value problem 2 using the leray schauder continuation theorem 2 we give an example of a three point boundary value problem where the existence condition is not satisfied and no solution exists gupta 3 recently studied the boundary value problem 2 when q 1 our results on the three point boundary value problem 2 extend the results of gupta 3 to the case of general cy see also 4 51 we use the classical spaces c o 11 c o 11 lk o 11 and l o l of continuous k times continuously differentiable measurable real valued functions whose kth power of the absolute value is lebesgue integrable on 0 11 or measurable functions that are essentially bounded

upper and lower solutions method and a second order three point singular boundary value problem the singular boundary value problem u q t g t u u 0 t 0 1 h 0 1 c 0 1 u 0 0 u 1 cu h is studied in this paper the singularity may appear at t 0 and the function g may be superlinear at u and change sign the existence of solutions is obtained via an upper and lower solutions method

three positive solutions for second order m point boundary value problems for the second order m point boundary value problemu t f t u 0 0 0 i 1 2 m 2 0 x 1 x 2 x m 2 1 growth conditions are imposed on f which yield the existence of at least three positive solutions by using the leggett williams fixed point theorem the associated green s function for the m point boundary value problem is also given

existence and iteration of positive solutions for a generalized right focal boundary value problem with p laplacian operator abstract in the paper we obtain the existence of positive solutions and establish a corresponding iterative scheme for the following third order generalized right focal boundary value problem with p laplacian operator p u t q t f t u t 0 t 1 u 0 i 1 m i u i u 0 u 1 i 1 n i u i the main tool is the monotone iterative technique

a p laplacian problem with a multi point boundary condition in this paper we will use the degree theory to give an existence result to the boundary value problem of nonlinear perturbations of the scalar p laplacian with the multi point boundary condition involving the lebesgue stieltjes integral among the boundary conditions considered in this paper we will find also the optimal bounds on the growth of the nonlinear perturbations in our existence result 2004 elsevier ltd all rights reserved

existence of multiple positive solutions for nonlinear m point boundary value problems abstract in this paper we afford some sufficient conditions to guarantee the existence of multiple positive solutions for the nonlinear m point boundary value problem for the one dimensional p laplacian p u a t f t u 0 t 0 1 u 0 0 u 1 i 1 m 2 a i u i

a dirichelet neumann m point bvp with a p laplacian like operator abstract let be odd increasing homeomorphisms from r onto r satisfying 0 0 0 and let f a b r r r be a function satisfying carath e odory s conditions let i r i a b i 1 m 2 a 1 2 m 2 b be given we are interested in the problem of existence of solutions for the m point boundary value problem u f t u u t a b u a 0 u b i 1 m 2 i u i in the resonance and non resonance cases we say that this problem is at resonance if the associated problem u 0 t a b u a 0 u b i 1 m 2 i u i has a non trivial solutions this is the case if and only if i 1 m 2 i 1 our results use topological degree methods interestingly enough in the non resonance case i e when i 1 m 2 i 1 the sign of degree for the relevant operator depends on whether i 1 m 2 i 1 or i 1 m 2 i 1

positive solutions of m point boundary value problems the second order m point boundary value problem x h x f x 0 0 x 1 0 0 1 i 1m 2ai i is considered under some conditions concerning the first eigenvalue of the relevant linear operator where i 0 1 with 0 1 2 m 2 1 ai 0 with i 1m 2ai 1 h x is allowed to be singular at x 0 and x 1 the existence of positive solutions and multiple positive solutions is obtained by means of fixed point index theory similarly conclusions hold for some other m point boundary value conditions

triple positive solutions for a multi point boundary value problem with a one dimensional p laplacian in this paper we consider the multiplicity of positive solutions for a one dimensional p laplacian differential equation with sturm liouville like boundary conditions by means of a fixed point theorem for cones in banach spaces we provide sufficient conditions for the existence of multiple positive solutions to the above boundary value problems

single tap precoders and decoders for multiuser mimo fbmc oqam under strong channel frequency selectivity the design of linear precoders or decoders for multiuser multiple input multiple output filterbank multicarrier fbmc modulations in the case of a strong channel frequency selectivity is presented the users and the base station bs communicate using space division multiple access the low complexity proposed solution is based on a single tap per subcarrier precoding decoding matrix at the bs in the downlink uplink as opposed to classical approaches that assume flat channel frequency selectivity at the subcarrier level the bs does not make this assumption and takes into account the distortion caused by channel frequency selectivity the expression of the fbmc asymptotic mean squared error mse in the case of strong channel selectivity derived in earlier works is developed and extended the linear precoders and decoders are found by optimizing the mse formula under two design criteria namely zero forcing or minimum mse finally simulation results demonstrate the performance of the optimized design as long as the number of bs antennas is larger than the number of users it is shown that those extra degrees of freedom can be used to compensate for the channel frequency selectivity

positive solutions of an m point boundary value problem with sign changing nonlinearities let a i 0 for i 1 m 2 let x i satisfy 0 x 0 x 1 x 2 x m 2 x m 1 1 and m 2 i 1a email protected i 1 we study the existence of positive solutions to the boundary value problem u f t u 0 0

positive solutions of singular three point boundary value problems for second order differential equations in this paper we study the existence of positive solutions of a singular three point boundary value problem for the following second order differential equation y ma t f t y t 0 t 0 1 y 0 by 0 0 y 1 ay h where m 0 is a parameter b 0 0 0 by constructing an available integral operator and combining fixed point index theory with properties of green s function under some conditions concerning the first eigenvalues corresponding to the relevant linear operator the sufficient conditions of the existence of positive solutions for the boundary value problems are established the interesting point of the results is that the term a t may be singular at t 0 and or t 1 moreover the nonlinear f t x is also allowed to have singularity at x 0