The influence of merging on h-type indices

Each information production process has a unique h-index. This paper studies the problem: what are possible h-index values if we merge two or more IPPs? First the paper gives examples of IPP mergings. There are at least two types: one where common sources add their number of items and one where common sources get the maximum of their number of items in the two IPPs. In each case we show that max(h(1), h(2)) <= h <= h(1) + h(2) for both types of mergings (h(i), i = 1, 2 the h-index in the two IPPs; h is the h-index in the merged one). We show that the above inequalities cannot be improved ( in both merging types). We also show that the same inequalities are true for the g-index and the R-index but that they are false for the weighted h-index. For the R-index we can even refine the above inequality R <= root R-1(2) + R-2(2) < R-1 + R-2. (C) 2008 Elsevier Ltd. All rights reserved.