Electronics industry is one of the fastest growing industries in the world. In India also, there are high turnovers and growing demand of electronics product especially after post liberalization in early nineties. These products generate e-waste which has become big environmental issue. Industries can handle these e-waste and product returns efficiently by developing reverse logistics (RL) syst...

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The Padmakar–Ivan (PI) index of a graph G is defined as the sum of terms [mu(e) + mv(e)] over all edges of G, where e is an edge, connecting the vertices u and v, wheremu(e) is the number of edges of G lying closer to the vertex u than to the vertex v, and where mv(e) is defined analogously. The extremal values of the PI index are determined in the class of connected bipartite graphs with a giv...