the first geometric-arithmetic index was introduced in the chemical theory as the summationof 2 du dv /(du  dv ) overall edges of the graph, where du stand for the degree of the vertexu. in this paper we give the expressions for computing the first geometric-arithmetic index ofhexagonal systems and phenylenes and present new method for describing hexagonal systemby corresponding a simple graph...

this paper presents an analytical view of variance reduction by control variate technique for pricing arithmetic asian options as a financial derivatives. in this paper, the effect of correlation between two random variables is shown. we propose an efficient method for choose suitable control in pricing arithmetic asian options based on the control variates (cv). the numerical experiment shows ...