The object of the present paper is to study certain curvature restriction on an LP-Sasakian manifold with a coefficient . Among others it is shown that if an LP-Sasakian manifold with a coefficient is a manifold of constant curvature, then the manifold is the product manifold. Also it is proved that a 3-dimensional Ricci semisymmetric LP-Sasakian manifold with a constant coefficient is a spaceform.

In this paper, we consider a generalized Riemann problem of the first order hyperbolic conservation laws. For the case that excludes the centered wave, we prove that the generalized Riemann problem admits a unique piecewise smooth solution u = u(t, x), and this solution has a structure similar to the similarity solution u = of the correspondin Riemann problem in the neighborhood of the origin provided that the coefficients of the system and the initial conditions are sufficiently smooth.

In this paper we prove that every Jordan -derivation on a Lie triple system is a -derivation. Specially, we conclude that every Jordan derivation on a Lie triple system is a derivation.

We consider the univalence function classes T, , and S(p). For these classes we shall study some univalence properties for a general integral operator. Furthermore we shall extend some known univalence criteria, i.e., Becker-type criteria.

In this paper we give a non-existence theorem for Hopf real hypersurfaces in complex two-plane Grassmannians satisfying the condition that the structure Jacobi operator commutes with the 3-structure tensors , i = 1, 2, 3.

This paper deals with the regularity properties for a class of semilinear integrodifferential functional differential equations. It is shown the relation between the reachable set of the semilinear system and that of its corresponding linear system. We also show that the Lipschitz continuity and the uniform boundedness of the nonlinear term can be considerably weakened. Finally, a simple example to which our main result can be applied is given.

We define a quarter symmetric metric connection in an almost r-paracontact Riemannian manifold and we consider invariant, noninvariant and anti-invariant hypersurfaces of an almost r-paracontact Riemannian manifold endowed with a quarter symmetric metric connection.

We obtain two new characterizations of separativity of refinement monoids, in terms of comparability-type conditions. As applications, we get several equivalent conditions of separativity for exchange ideals.

For a Borel function satisfying the functional equation (s + t, u + v) + (s - t, u - v) = (s, u) + (t, v), we show that it satisfies the functional equation (s, t) = s(s - t)(1, 0) + (1, 1) + t(t - s)(0, 1). Using this, we prove the stability of the functional equation f(ax + ay, bz + bw) + f(ax - ay, bz - bw) = 2abf(x, z) + 2abf(y,w) in Banach modules over a unital -algebra.

A matrix is called a generalized reflection matrix if = P and = I. An complex matrix A is said to be a reflexive (anti-reflexive) matrix with respect to the generalized reflection matrix P if A = PAP (A = -PAP). It is well-known that the reflexive and anti-reflexive matrices with respect to the generalized reflection matrix P have many special properties and widely used in engineering and scientific computations. In this paper, we give new necessary and sufficient conditions for the existence of the reflexive (anti-reflexive) solutions to the linear matrix equation AXB + CY D = E and derive representation of the general reflexive (anti-reflexive) solutions to this matrix equation. By using the obtained results, we investigate the reflexive (anti-reflexive) solutions of some special cases of this matrix equation.

In this paper we present new large-update primal-dual interior point algorithms for linear complementarity problems(LAPS) based on a class of kernel functions, , p [0, 1], . It is the first to use this class of kernel functions in the complexity analysis of interior point method(IPM) for LAPS. We showed that if a strictly feasible starting point is available, then new large-update primal-dual interior point algorithms for LAPS have complexity bound. When p = 1, we have complexity which is so far the best known complexity for large-update methods.

In this paper we study some properties of the Helton class of an operator. In particular, we show that the Helton class preserves the quasinilpotent property and Dunford's boundedness condition (B). As corollaries, we get that the Helton class of some quadratically hyponormal operators or decomposable subnormal operators satisfies Dunford's boundedness condition (B).

We investigate the behavior of maps in minimal injective resolution of an A-module M when (m,M) = 1 for some t, and we develop slightly the fact that a module of type 1 is Cohen-Macaulay.

In this paper we prove that every generalized Jordan triple higher derivation on a 2-torsion free semiprime ring is a generalized higher derivation. This extend the main result of [9] to the case of a semiprime ring.

We classify and characterize the rational helicoidal surfaces in a three-dimensional Minkowski space satisfying pointwise 1-type like problem on the Gauss map.

In this paper, we give a classification of contact 3-manifolds whose Ricci tensors are -parallel.

This paper studies the relations between ideals, filters, regular congruences and normal congruences in inclines. It is shown that for any incline, there are a one-to-one correspondence between all ideals and all regular congruences and a one-to-one correspondence between all filters and all normal congruences.

Let R be a prime ring, H a generalized derivation of R and L a noncommutative Lie ideal of R. Suppose that = 0 for all u L, where s 0, t 0 are fixed integers. Then H(x) = 0 for all x R unless char R = 2 and R satisfies , the standard identity in four variables.