Hi Nathann, On Apr 22, 2014, at 6:44 PM, Nathann Cohen <nathann.co...@gmail.com> wrote:
> Yoooooooooooooooooooo !! > > But, of course, this design extends uniquely to a (necessarily) 2-(4n, 2n, > n-1) design: the blocks of this design are blocks of the old design union a > new point infinity and complements (in the old point set) of the blocks of > old design. And, any contraction is isomorphic to a Hadamard 2-design we > started off with. So, unsurprisingly, this family is called Hadamard > 3-designs. > > As you see, implementing the 3-design is trivial but we should settle down on > the nomenclature! > > I did not know about this construction, but the Handbook agrees with you, so > why not ? :-D > > By the way your proof of it is very cool. > > So, what do you guys think? > > Do you feel like creating a ticket and writing this patch ? I will be glad to > review it quickly. > Sure, I can do this if someone would help me with GIT. I have been keeping away from SAGE mainly for this reason! Anyway, I created the ticket: http://trac.sagemath.org/ticket/16211. And, we still have not thought about the nomenclature... :-) May be change the Hadamard design to HadamardTwoDesign and implement these as HadamardThreeDesign? Also, probably, we should have a generic implementation of block design, where one gives us the point set, the blocks but is interested in computing parametric things with it; or computing the derived design and so on... (This is done in Designs package in GAP, so may be we should just borrow it!) > p/s/ Thanks Nathann for implementing the combinat.designs! I am a big fan of > designs and it is nice to have them in SAGE. > > Well, I am pretty glad that you noticed the changes and that you like them. > If you have time to review some code, there are a couple of things that are > still waiting on the trac server : > > A straightforward one : http://trac.sagemath.org/ticket/16091 > A more interesting one : http://trac.sagemath.org/ticket/15310 > GIT again is the barrier! :-( -Kannappan. > (Vincent just reviewed http://trac.sagemath.org/ticket/15431 ) > > The second one is a very interesting recursive construction that I need to > add the general construction of BIBD with k=5 (which already works on my > computer). There will also be a need for a patch that just cleans the code in > between before that. > > Well, this just to say that if you feel like getting your hands dirty for > Sage's designs... ;-) > > Have fuuuuuuuuuuuun ! > > Nathann > > -- > 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 http://groups.google.com/group/sage-devel. > For more options, visit https://groups.google.com/d/optout. > <a.jpg> -- 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 http://groups.google.com/group/sage-devel. For more options, visit https://groups.google.com/d/optout.
