Hi,
On Mon, Jan 30, 2017 at 03:44:06AM -0800, jamel Dammak wrote:
> 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=G
> raph({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
> #[2,4] is a module of g2 so g2 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.
Great, go ahead, ask for a trac account, and propose your changes.
http://doc.sagemath.org/html/en/faq/faq-contribute.html
Ciao,
Thierry
>
> Best regards.
>
> --
> 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 sage-devel+unsubscr...@googlegroups.com.
> To post to this group, send email to sage-devel@googlegroups.com.
> Visit this group at https://groups.google.com/group/sage-devel.
> 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 sage-devel+unsubscr...@googlegroups.com.
To post to this group, send email to sage-devel@googlegroups.com.
Visit this group at https://groups.google.com/group/sage-devel.
For more options, visit https://groups.google.com/d/optout.
