Study on the Relation of Definite Integral and Indefinite Integral

Relation of definite integral and indefinite integral was discussed and an important result was gotten. If f(x) is bounded and has primary function, the formal definite integral x s f(t)dt is the indefinite integral of f(x), where x is a self-variable, s is a parameter,~f(x) is a function defined in(-∞, +∞), which comes from f(x) by restriction and extension. In other words, the indefinite integral is a special form of definite integral, its lower integral limit and upper integral limit are all indefinite.     

RESEARCH ANNOUNCEMENTS Rough Marcinkiewicz Integrals With L(log~ L)~2 Kernels on Product Spaces

Let RN (N 2, N = n or m) be the N-dimensional Euclidean space and SN-1 be the unitsphere in RN. For nonzero point x RN, we denote x' = x/ |x|. E. M. Stein[12] defined a highdimensional analogue of the Marcinkiewicz integral on Rn by (f)(x)= (R|Fs(x)|2ds)1/2,where Fs(x) =dv, is a homogeneous function of degree zero, whoserestriction to Sn-1 is in L1 (Sn-1) and satisfies the cancellation property sn-1 (x')dx'= 0. Itis well-known that the Marcinkiewicz integral is very useful in harmonic…     

RESEARCH ANNOUNCEMENTS Rough Marcinkiewicz Integrals With L（log＋L）^2 Kernels on Product Spaces

Let Rv (N>2,N＝n or m)be the N-dimensional Euclidean space and SN-1 be the unit sphere in Rv.For nonzero point x E RN,we denote x＇＝x/|x|. E.M.Stein[12]defined a high dimensional analogue of the Marcinkiewicz integral on Rn byμΩ(f)(x)＝(∫n|Fs(x)|2 ds)1/2,where Ωis a homogeneous function of degree zero, whose restriction to Sn-1 is in L1(Sn-1) and satisfies the cancellation property ∫sn-1Ω(x＇)dx＇＝0.It is well-known that the Marcinkiewicz integral is very useful in harmonic analysis. Readers can see [1, 2, 5, 7, 9-13],among numerous references,for its development and applications.     

Positive Solutions of Hammerstein Nonlinear Integral Equations

In this paper we consider the Hammerstein nonlinear integral equation (x)=integral from G (K(x,y) f(y,(y))dy=A(x)) (1) where G is a bounded closed domain in R"; the function f(x,u) is non-negative,continuous on G×[0,+∞) and f(x,0)≡0; the kernel k(x,y) is non-negative continuous on G×G. Obviously, A acts in the space C(G) and is completely continuous. Theorem 1 Suppose that (i) lim u~(-1)f(x,u)=0 and lim u~(-1)f(x, u)=+∞     

On the Number of Integral Ideals in Two Different Quadratic Number Fields

Let K be an algebraic number field of finite degree over the rational field Q,and a K(n) the number of integral ideals in K with norm n. When K is a Galois extension over Q, many authors contribute to the integral power sums of a K(n),Σn≤x a K(n)~l, l = 1, 2, 3, ···.This paper is interested in the distribution of integral ideals concerning different number fields. The author is able to establish asymptotic formulae for the convolution sum Σn≤x aK_1(n~j)~laK_2(n~j)~l, j = 1, 2, l = 2, 3, ···,where K_1 and K_2 are two different quadratic fields.     

Liouville theorems for an integral system with Poisson kernel on the upper half space

We investigate the Liouville theorem for an integral system with Poisson kernel on the upper half space R_+~n,{u(x) =2/(nω_n)∫_(?R_+~n)(xnf(v(y)))/(|x- y|~n)dy, x ∈R_+~n,v(y) =2/(nω_n)∫_(R_+~n)(xng(u(x)))/(|x- y|~n)dx, y ∈?R_+~n,where n 3, ωn is the volume of the unit ball in Rn. This integral system arises from the Euler-Lagrange equation corresponding to an integral inequality on the upper half space established by Hang et al.(2008).With natural structure conditions on f and g, we classify the positive solutions of the above system based on the method of moving spheres in integral form and the inequality mentioned above.     

General ARMA Models

1.Introduction Consider the following model A(B)x(t)=w(t) t=1,2,…(1)where B denotes the Backwards shift operation,i.e.Bx(t)=x(t-1),B~2x(t)=x(t-2),and so on; A(B)is a polynomial of B, A(B)=1-a_1B-a_2B~2-…-a,B~r (2)with its roots laid on and at inside of the unit circle; and w(t) is a stationaryARMA(p,q)process,i. e. w(t) satisfies     

Integral closure of a quartic extension

Let R be a Noetherian unique factorization domain such that 2 and 3 are units,and let A=R[α]be a quartic extension over R by adding a rootαof an irreducible quartic polynomial p(z)=z4+az2+bz+c over R.We will compute explicitly the integral closure of A in its fraction field,which is based on a proper factorization of the coefficients and the algebraic invariants of p(z).In fact,we get the factorization by resolving the singularities of a plane curve defined by z4+a(x)z2+b(x)z+c(x)=0.The integral closure is expressed as a syzygy module and the syzygy equations are given explicitly.We compute also the ramifications of the integral closure over R.     

Symmetry and regularity of solutions to a system with three-component integral equations

Consider the system with three-component integral equations u(x) = Rn |x y|α nw(y)rv(y)q dy,v(x) = Rn |x y|α nu(y)pw(y)rdy,w(x) = Rn |x y|α nv(y)q u(y)pdy,where 0 < α < n,n is a positive constant,p,q and r satisfy some suitable conditions.It is shown that every positive regular solution(u(x),v(x),w(x)) is radially symmetric and monotonic about some point by developing the moving plane method in an integral form.In addition,the regularity of the solutions is also proved by the contraction mapping principle.The conformal invariant property of the system is also investigated.     

Linear Volterra Integral Equations as the Limit of Discrete Systems

We consider the multidimensional abstract linear integral equation of Volterra type x（t） （*）∫Rtα（s)x(s)ds=f(t),t∈R,（1）as the limit of discrete Stieltjes-type systems and we prove results on the existence of continuous solutions. The functions x, α and f are Bauach space-valued defined on a compact interval R of R^n Rt is a subinterval of R depending on t ∈ R and (*) f denotes either the Bochner-Lebesgue integral or the Henstock integral. The results presented here generalize those in [1] and are in the spirit of [3]. As a consequence of our approach, it is possible to study the properties of (1) by transferring the properties of the discrete systems, The Henstock integral setting enables us to consider highly oscillating functions.     

Uniqueness to Some Inverse Source Problems for the Wave Equation in Unbounded Domains

This paper is concerned with inverse acoustic source problems in an unbounded domain with dynamical boundary surface data of Dirichlet kind. The measurement data are taken at a surface far away from the source support. We prove uniqueness in recovering source terms of the form f(x)g(t) and f(x1, x2, t)h(x3),where g(t) and h(x3) are given and x =(x1, x2, x3) is the spatial variable in three dimensions. Without these a priori information, we prove that the boundary data of a family of solutions ca...     

Symmetry and nonexistence of positive solutions to an integral system with weighted functions

Consider the system of integral equations with weighted functions in Rn,{u(x) =∫Rn|x-y|α-nQ(y)v(y)qdy1,v(x)=∫Rn|x-y|α-nK(y)u(y)pdy,where 0 < α < n,1/(p+1) + 1/(q+1)≥(n-α)/n1,α/(n-α) < p1q < ∞1,Q(x) and K(x) satisfy some suitable conditions.It is shown that every positive regular solution(u(x)1,v(x)) is symmetric about some plane by developing the moving plane method in an integral form.Moreover,regularity of the solution is studied.Finally,the nonexistence of positive solutions to the system in the case 0 <...     

A sharp estimate of positive integral points in 6-dimensional polyhedra and a sharp estimate of smooth numbers

Inspired by Durfee Conjecture in singularity theory, Yau formulated the Yau number theoretic conjecture(see Conjecture 1.3) which gives a sharp polynomial upper bound of the number of positive integral points in an n-dimensional(n≥3) polyhedron. It is well known that getting the estimate of integral points in the polyhedron is equivalent to getting the estimate of the de Bruijn function ψ(x, y), which is important and has a number of applications to analytic number theory and cryptography. We prove the Yau number theoretic conjecture for n = 6. As an application, we give a sharper estimate of function ψ(x, y) for 5≤y 17, compared with the result obtained by Ennola.     

A GENERALIZATION OF LEBESGUE DIFFERENTIAL THEOREM AND ITS APPLICATION

1 IntroductionLet fl C Rn. Classical Lebesgue differential theorem says:u(x) = liny IB.(x)l--' j u(y)dy a.e. in fl Vu E L'(fl),r-o js.(.)"(y)dy a.e. in fl Vu E L'(fl),where, Br(x) is the euclidean metric ball witl1 radius r and center x; IB.(x)I is the Lebesguemeasure of B.(x). Taking use of it, one can deduce Canpanato's integral chaxacterization ofH5lder continuous f[1nctions and Morrey's growing theorem of Dirichlet integration which playan imPortant role in regularity theories of …     

The definite integral

<正>1.What does the definite integral mean?The definite integral of f(x)fromato b is defined the limit of the sum as n→∞.That is limn→∞∑n i=1f(ξi)·Δxi.We divide the interval[a,b]into n subintervals of equal widthΔx=(b-a)n.Let x0=a,x1,x2,…,xn=b be the endpoints of these subintervals and we chooseξiis any point in the ith subinterval,that is,xi-1≤ξi≤xi,then,the sum∑n f(ξi)·Δxiis called a Rie-     

Variational Problems of Surfaces in a Sphere

Let x : M → S~(n+p)(1) be an n-dimensional submanifold immersed in an(n + p)-dimensional unit sphere S~(n+p)(1).In this paper, we study n-dimensional submanifolds immersed in S~(n+p)(1) which are critical points of the functional S(x) =∫_M~S~((n/2) dv), where S is the squared length of the second fundamental form of the immersion x.When x : M → S~(2+p)(1) is a surface in S~(2+p)(1), the functional S(x) =∫_M~(S~(n/2) dv) represents double volume of image of Gaussian map.For the critical surface of S(x), we get a relationship between the integral of an extrinsic quantity of the surface and its Euler characteristic.Furthermore, we establish a rigidity theorem for the critical surface of S(x).     

Pointwise Fourier inversion of distributions

We show that,given a tempered distribution T whose Fourier transform is a function of polynomial growth and a point x in Rn at which T has the value τ(in the sense of Lojasiewicz),the Fourier integral of T at x is summable in Bochner-Riesz means to τ.     

Legendre spectral collocation method for volterra-hammerstein integral equation of the second kind

This paper is concerned with obtaining the approximate solution for VolterraHammerstein integral equation with a regular kernel. We choose the Gauss points associated with the Legendre weight function ω(x) = 1 as the collocation points. The Legendre collocation discretization is proposed for Volterra-Hammerstein integral equation. We provide an error analysis which justifies that the errors of approximate solution decay exponentially in L~2 norm and L~∞ norm. We give two numerical examples in order to illustrate the validity of the proposed Legendre spectral collocation method.     

Fractal dimensions of fractional integral of continuous functions

In this paper,we mainly explore fractal dimensions of fractional calculus of continuous functions defined on closed intervals.Riemann–Liouville integral of a continuous function f(x) of order v(v0) which is written as D~(-v) f(x) has been proved to still be continuous and bounded.Furthermore,upper box dimension of D~(-v) f(x) is no more than 2 and lower box dimension of D~(-v) f(x) is no less than 1.If f(x) is a Lipshciz function,D~(-v) f(x) also is a Lipshciz function.While f(x) is differentiable on [0,1],D~(-v) f(x) is differentiable on [0,1] too.With definition of upper box dimension and further calculation,we get upper bound of upper box dimension of Riemann–Liouville fractional integral of any continuous functions including fractal functions.If a continuous function f(x) satisfying H?lder condition,upper box dimension of Riemann–Liouville fractional integral of f(x) seems no more than upper box dimension of f(x).Appeal to auxiliary functions,we have proved an important conclusion that upper box dimension of Riemann–Liouville integral of a continuous function satisfying H?lder condition of order v(v0) is strictly less than 2-v.Riemann–Liouville fractional derivative of certain continuous functions have been discussed elementary.Fractional dimensions of Weyl–Marchaud fractional derivative of certain continuous functions have been estimated.     

Weighted polyharmonic equation with Navier boundary conditions in a half space

We study positive solutions of the following polyharmonic equation with Hardy weights associated to Navier boundary conditions on a half space:?????(-?)~mu(x)=u~p(x)/|x|~s,in R_+~n,u(x)=-?u(x)=…=(-?)~(m-1)u(x)=0,on ?R_+~n,(0.1)where m is any positive integer satisfying 02mn.We first prove that the positive solutions of(0.1)are super polyharmonic,i.e.,(-?)~iu0,i=0,1,...,m-1.(0.2) For α=2m,applying this important property,we establish the equivalence between (0.1) and the integral equation u(x)=c_n∫R_+~n(1/|x-y|~(n-α)-1/|x~*-y|~(n-α))u~p(y)/|y|~sdy,(0.3) where x~*=(x1,...,x_(n-1),-x_n) is the reflection of the point x about the plane R~(n-1).Then,we use the method of moving planes in integral forms to derive rotational symmetry and monotonicity for the positive solution of(0.3),in whichαcan be any real number between 0 and n.By some Pohozaev type identities in integral forms,we prove a Liouville type theorem—the non-existence of positive solutions for(0.1).