@techreport{TR-IC-18-07, number = {IC-18-07}, author = {João Paulo Pereira Zanetti and João Meidanis}, title = {Counting sorting scenarios and intermediate genomes for the rank distance}, month = {April}, year = {2018}, institution = {Institute of Computing, University of Campinas}, note = {In English, 23 pages. \par\selectlanguage{english}\textbf{Abstract} An important problem in genome comparison is the genome sorting problem, that is to find a sequence of basic operations that transforms one genome into another and corresponds to the distance between them. These sequences are called optimal sorting scenarios. However, there is usually a large number of such scenarios, and a naive algorithm is very likely to be biased towards a specific type of scenario, impairing its usefulness in real-world applications. One way to go beyond the traditional sorting algorithms is to explore all possible solutions, looking at all the optimal sorting scenarios instead of just an arbitrary one. Another approach in the same direction is to analyze all the intermediate genomes, that is, all genomes that are part of an optimal sorting scenario. In this paper, we show how to count the number of optimal sorting scenarios and the number of intermediate genomes between any two given genomes, under the rank distance. } }