When comparing the citation impact of nations, departments or other groups of researchers within individual fields, three approaches have been proposed: arithmetic means, geometric means, and percentage in the top X%. This article compares the precision of these statistics using 97 trillion experimentally simulated citation counts from 6875 sets of different parameters (although all having the ...

We study the computational complexity of the qualitative algebra which is a temporal formalism that combines the point algebra, the point-interval algebra and Allen’s interval algebra. We identify all tractable fragments containing the point algebra and show that, for all other fragments containing the point algebra, the problem is NP-complete.