A Helly circular-arc graph is the intersection graph of a set of arcs on a circle having the Helly property. We introduce essential obstacles, which are a refinement of the notion of obstacles, and prove that essential obstacles are precisely the minimal forbidden induced circular-arc subgraphs for the class of Helly circular-arc graphs. We show that it is possible to find in linear time, in an...

A rectangular dual of a graph G is contact representation by axis-aligned rectangles such that (i) no four share point and (ii) the union all rectangle. The partial extension problem for duals asks whether given can be extended to dual, is, there exists where some vertices are represented prescribed rectangles. simultaneous two (or more) graphs subgraph admit coincide on shared subgraph. Combin...

To calculate partial and total productivity of production factors in broiler farms in Yazd province, 72 manufacturing units were selected based on simple random sampling method and their information and statistics were collected for one production period in the second half of 2013. To measure productivity, the Cobb-Douglas production function was estimated using classic and fuzzy regression met...

A subgraph isomorphism problem consists in deciding if there exists a copy of a pattern graph in a target graph. We introduce in this paper a filtering algorithm dedicated to this problem. The main idea is to label every node with respect to its relationships with other nodes of the graph, and to define a partial order on these labels in order to express compatibility of labels for subgraph iso...

For each pair of graphs from among the Archimedean lattices and their dual Laves lattices we demonstrate that one is a subgraph of the other or prove that neither can be a subgraph of the other. Therefore, we determine the entire partial ordering by inclusion of these 19 infinite periodic graphs. There are a total of 72 inclusion relationships, of which 35 are covering relations in the partial ...

In classical graph theory, the minimal spanning tree (MST) is a subgraph with no cycles that connects each vertex minimum edge weights. Calculating of has always been common problem throughout ages. Fuzzy (FMST) able to handle uncertainty existing in weights for fuzzy which occurs real world situations. this article, we have studied MST directed and undirected whose are represented by fermatean...

Artificial intelligent techniques have been widely used in high voltage insulation technology application. In this paper, the effectiveness of artificial intelligent technique to apply for pattern recognition and classification of Partial Discharge (PD) is presented. Partial discharge signal was generated and measured by using an artificial partial discharge source. Characteristics of PD signal...

Let F, G and H be non-empty graphs. The notation F → (G,H) means that if any edge of F is colored by red or blue, then either the red subgraph of F con- tains a graph G or the blue subgraph of F contains a graph H. A graph F (without isolated vertices) is called a Ramsey (G,H)−minimal if F → (G,H) and for every e ∈ E(F), (F − e) 9 (G,H). The set of all Ramsey (G,H)−minimal graphs is denoted by ...