Here is a try Z=species.SingletonSpecies() E2=species.SetSpecies(min=2) P=CombinatorialSpecies() S=CombinatorialSpecies() P.define(E2.composition(Z+S)) S.define(E2.composition(Z+P)) N=Z+P+S
That seems to work : sage: koko=N.generating_series().coefficients(8) sage: [koko[i]*factorial(i) for i in range(len(koko))] [0, 1, 2, 8, 52, 472, 5504, 78416] compare with https://oeis.org/A006351 Frederic On 25 juil, 13:12, Frank Zenter <zent...@gmail.com> wrote: > Dear combinat-developers, > > for my research I would lik to study thespeciesof series-parallel > networks. > In EOIS as sloane.A006351 they propose the combstruct-code > > spec := [ N, {N=Union(Z, S, P), S=Set(Union(Z, P), card>=2), > P=Set(Union(Z, S), card>=2)}, labeled ]: > > How can I make that using sage-combinat? > > A search in the reference manual did not help, so I hope you can help > me. > (by the way: there seems to be a typo in the manual. As operations onSpecies > the second item should read "ProductSpecies" and not "SumSpecies") > > Thank you for your help. > > Frank -- You received this message because you are subscribed to the Google Groups "sage-combinat-devel" group. To post to this group, send email to sage-combinat-devel@googlegroups.com. To unsubscribe from this group, send email to sage-combinat-devel+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/sage-combinat-devel?hl=en.
