Iranian Journal of Mathematical Sciences and Informatics
Year:2006 | Volume:1 | Issue:2|Papers Count:6

For a unital foundation topological *-semi group S whose representations separate points of S, we show that the spectrum of the Fourier-Stieltjes algebra B(S) is a compact semi topological semi group. We also calculate B(S) for several examples of S.

In this paper we consider a kind of higher-order evolution equation as ¶ku/¶tk+¶k-1u/¶1k-1 + ...+ U1-Du=f(u, Du,x). For this equation, we investigate nonglobal solution, blow-up in finite time and instantaneous blow-up under some assumption on k, f and initial data. In this paper we employ the Test function method, the generalized convexity method and Galerkin's method for some of our proofs. Moreover, occasionally by changing P.D.E problems to some ordinary differential inequalities, we investigate this kind of higher-order evolution equations.

Involving the Ricci curvature and the squared mean curvature, we obtain basic inequalities for different kind of submanifolds of a Sasakian space form tangent to the structure vector field of the ambient manifold. Contrary to already known results, we find a different necessary and sufficient condition for the equality case. We also give very simple proofs (1) for a basic inequality for Ricci curvature of C-totally real sub manifolds of a Sasakian space form, and (2) of the fact that if a C-totally real sub manifold of maximum dimension satisfies the equality case, then it must be minimal. Two basic inequalities for sub manifolds of any Riemannian manifold, one involving scalar curvature and the squared mean curvature and the other involving the invariant  qk and the squared mean curvature are also obtained. These results are applied to get corresponding results for sub manifolds of Sasakian space forms.

For any hÎN, a graph G = (V, E) is said to be h-magic if there exists a labeling I: E(G)® Zh - {0} such that the induced vertex set labeling .l+ : V(G)® Zh defined by l+(v) = SuvÎE(G) L(uv) is a constant map. For a given graph G, the set of all hÎZ + for which G is h-magic is called the integer-magic spectrum of G and is denoted by IM(G). In this paper, the integer-magic spectra of certain classes of cycle related graphs will be determined.

A tree T of order n is called k-placeable if there are k edgedisjoint copies of T into Kn. In this paper we prove some results about 4-placement of rooted trees.

In this paper, we consider characterizations based on the Bhattacharyya matrices. We characterize, under certain constraint, distributions such as normal, compound poisson and gamma via the diagonality of the 2 x 2 Bhattacharyya matrix.