Iranian Journal of Mathematical Sciences and Informatics
Volume:3 Issue: 2, Nov 2008

The vertex version of detour index was defined during the works on connected graph in chemistry. The edge versions of detour index have been introduced ecently. In this paper, the explicit relations among edge versions of detour index have been declared and due to these relations, we compute the edge detour indices for some well-known graphs

In this paper, He’s homotopy perturbation method is applied to solve linear Schrodinger equation. The method yields solutions in convergent series forms with easily computable terms. The result show that these method is very convenient and can be applied to large class of problems. Some numerical examples are given to effectiveness of the method.

In this paper, two methods are described, by means of which it is possible to calculate the non rigid group of molecules consisting of a number of XH3 groups attached to a rigid framework. The first method is a combination of the wreath product formalism of Balasubramanian and modern computer algebra and the second method is a computational approach by using group theory package GAP. We apply these methods on 2,3,6,7,10,11-hexanitrotriphenylene (HNT) to compute its non-rigid group.

The notion of quasi-exact sequence of modules was introduced by B. Davvaz and coauthors in 1999 as a generalization of the notion of exact sequence. In this paper we investigate further this notion. In particular, some interesting results concerning this concept and torsion functor are given.

In this paper, we are presented a formula for the polynomial of a graph. Our main result is the following formula: [Sum (d{_u}(k))]=[Sum (a{_kj}{S{_G}^j}(1))], where, u is an element of V(G) and 1<=j<=k.

For a commutative semigroup S with 0, the zero-divisor graph of S denoted by Γ(S) is the graph whose vertices are nonzero zero-divisor of S, and two vertices x, y are adjacent in case xy = 0 in S. In this paper we study median and center of this graph. Also we show that if Ass(S) has more than two elements, then the girth of Γ(S) is three.

The superminimality of the fibres of an almost contact metric submersion is used to study the integrability of the horizontal distribution and the structure of the total space.