In this paper, we deal with restoring missing information in molecule databases: Some data formats only store the atoms’ configuration but omit bond multiplicities. As this information is essential for various applications in chemistry, we consider the problem of recovering bond type information using a scoring function for the possible valences of each atom—the Bond Type Assignment problem. We...

cospectrality of two graphs measures the differences between the ordered spectrum of these graphs in various ways. actually,the origin of this concept came back to richard brualdi's problems that are proposed in cite{braldi}:let $g_n$ and $g'_n$ be two nonisomorphic simple graphs on $n$ vertices with spectra$$lambda_1 geq lambda_2 geq cdots geq lambda_n ;;;text{and};;; lambda'_1 geq lambda'_2 g...

In this paper we study the calculus of circuits X , as first presented in [13] and studied in detail in [5]. We will present a number of new implementations of X using term graph rewriting techniques, which are improvements of the technique used in [6]. We will show that alpha conversion can be dealt with ‘on the fly’, and that explicit copying can be avoided, by presenting, discussing and comp...

Currently existing graph grammar-based speciication languages have serious problems with supporting any kind of \speciication-in-the-large" activities. More precisely , they have deeciences with respect to modeling hierarchical data structures or specifying meta activities like manipulation of graph schemata. Furthermore, already proposed graph grammar module concepts are still too abstract to ...

Greedy Forwarding algorithm is a widely-used routing algorithm for wireless networks. However, it can fail if the wireless network topologies contain void scenarios (or simply called voids). Since Yao Graph and Theta Graph are two types of geometric graphs exploited to construct wireless network topologies, this paper studies whether these two types of graphs can contain voids. Specifically, th...