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Abstract: For a molecular graph, the first Zagreb index is equal to the sum of squares of the vertex degrees and second Zagreb index is equal to the sum of products of degree of pairs of adjacent vertices. In this paper, Zagreb indices of polyomino chains are computed. Also the extremal polyomino chains with respect to Zagreb indices are determined. [Copyright &y& Elsevier]

Abstract: The focus of this paper is on issues arising from the comparison of business survey indices (BSI’s). Any BSI may be contaminated by false reports or contagion effects so that a crude comparison of BSI’s across different groups is not appropriate. A method is therefore proposed for transforming different business survey indices into comparable indices using the generalized birth and death process. The method is carefully designed in order to filter out contagion effects by taking respondents’ interaction into consideration. The method also improves the comparability of the BSI’s by adjusting the information precision of different survey groups. [Copyright &y& Elsevier]

In this paper, a new coincidence index is presented for countably P-concentrative pairs. [Copyright &y& Elsevier]

The Hosoya polynomial of a graph, H(G, x), has the property that its first derivative, evaluated at x = 1, equals the Wiener index, i.e., W(G) = H′(G, 1). In this paper, an equation is presented that gives the hyper-Wiener index, WW(G), in terms of the first and second derivatives of H(G, x). Also defined here is a hyper-Hosoya polynomial, HH(G, x), which has the property WW(G) = HH′(G, 1), analogous to W(G) = H′(G, 1). Uses of higher derivatives of HH(G, x) are proposed, analogous to published uses of higher derivatives of H(G, x). [Copyright &y& Elsevier]