IMPORTANT ANNOUNCEMENT An embarrassing off-by-one error was corrected in the programs that create random graphs (random_graph and random_bigraph). When making this change, I decided it was better to conform to the documentation than to remain totally compatible with past history. The graph that now is called random_graph(n,m,x,l,o,f,t,a,b,s), and which properly deserves that name, is the same as the graph that used to be called random_graph(n,m,x,l,o,f,t,a,b+1,s) --- unless a = b, in which case the old program was correct and no change was necessary. Please upgrade to the new versions of the SGB source programs, if your copy is dated earlier than July 1999.