Sooner or later it was bound to happen; this function relies on modular_decomposition optional package, which is very iffy, and ought to be removed or redone, see https://trac.sagemath.org/ticket/17950
Should we do something about it? @Harald - you can see the sender email by doing show source on the message; I put it into cc to this message. On Sunday, December 11, 2016 at 9:08:50 PM UTC, Harald Schilly wrote: > > This came in via the trac account request. I don't know the sender's > email address ... > > -- h > > > ---------- Forwarded message ---------- > From: 'Jamel Dammak' via sage-trac-account <[email protected] > <javascript:>> > Date: Sun, Dec 11, 2016 at 10:01 PM > Subject: [sage-trac-account] Corrections about the function "is_prime" > for graphs > To: "[email protected] <javascript:>" < > [email protected] <javascript:>> > > > Dear sir, > > there is an error concerning the function "is_prime" for graphs in > Sagemath, section Graph Theory. > > Here is a conter-example. > > g1=Graph({0:[1,4],1:[0,2,4],2:[1,3,4],3:[2],4:[0,1,2]});g2=Graph({0:[1],1:[0,2,4],2:[1,3,4],3:[2,4],4:[1,2,3]}) > > > #g1.show();g2.show(); > #[1,4] is a module of g1 so g1 is not prime > g2.is_isomorphic(g1), g1.is_prime(),g2.is_prime() > > This is a conter-example with two isomorphic graphs g1 and g2 on 5 > vertices giving two different results > with the function "is prime". > > I have an algorithm giving the list of all prime graphs on at most 8 > vertices. > > Best regards. > > -- > -- > You received this message because you are subscribed to the Google > Groups "sage-trac-account" group. > To post to this group, send email to [email protected] > <javascript:> > To unsubscribe from this group, send email to > [email protected] <javascript:> > For more options, visit this group at > http://groups.google.com/group/sage-trac-account > > --- > You received this message because you are subscribed to the Google > Groups "sage-trac-account" group. > To unsubscribe from this group and stop receiving emails from it, send > an email to [email protected] <javascript:>. > For more options, visit https://groups.google.com/d/optout. > -- You received this message because you are subscribed to the Google Groups "sage-devel" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at https://groups.google.com/group/sage-devel. For more options, visit https://groups.google.com/d/optout.
