CENTRE DE MATHEMATIQUES APPLIQUEES C.M.A.P. Statistical distribution of the convergence time for longpath problems Josselin Garnier Leila Kallel This paper studies the behavior of (1+1)-ES on Rudolph's k-longpaths. Expected convergence time is proven to be exponential for k equals a power of string length l. Statistical distribution of convergence time and its variance are calculated in the case of constant k. The influence of population size (as a function of l) is investigated. It comes that a population size with a growth rate of l quickens the search but cannot change the order of convergence time. Different evolution strategies are compared. The whole paper is available as a compressed Postscript file by internet procedure FTP anonymous on host barbes.polytechnique.fr ( 129.104.4.100) in the directory pub/RI/1998 under the name garnier_kallel_378.mars.ps.gz or by Netscape or any other www client via the CMAP www server http://www.cmap.polytechnique.fr