On Friday, 10 February 2017 21:50:18 UTC+1, Bill Page wrote: > > Hi Kurt, > > Thanks for tracking. I am sorry that I have not been doing such a > good job of pushing changes to github. The specific problems that you > see are the result of some experimentation. Things are still in a > state of fairly rapid evolution and I should have something new later > today, time permitting.
Not at all. I use github likewise ;) > As you noticed I have been experimenting with > different term orderings as I try to enrich the set of rewrite rules. > As might be expected I have found a few cases that result in > non-termination and have been looking for inspiration in the > literature. > Yes, still a popular and difficult topic ... > Of course there are many other and newer papers on this subject but I > have yet to find one that is a good match for what I am trying to do > right now. If you have any suggestions that would be great. My first source usually is: http://www21.in.tum.de/~nipkow/pubs/ and my zotero entries on the subject are: http://www.cs.tau.ac.il/~nachum/papers/termination.pdf (even older) http://www.informatik.uni-bremen.de/agbkb/lehre/rbs/texte/Klop-TR.pdf https://www.cs.cornell.edu/~ara/papers/vh05tocl.pdf But my knowledge on the subject beyond Knuth-Bendixon, Buchberger etc. is rather limited. Please let me know when it's forged ahead. Kurt > Bill. > > > On 9 February 2017 at 21:13, Kurt Pagani <nil...@gmail.com <javascript:>> > wrote: > > Bill, > > > > I pulled the latest version of sexpr.spad today and now get an error I > have no > > explanation for (I created a unit test file using the input from the > sandbox). > > > > Four of the seven errors (see tail of sexpr.output) are not errors as > such, only > > caused by the ordering. > > > > case ex2:20 and 21 might be caused by the Unittest itself, though I'm > not sure. > > > > case ex4:4 is strange: the rule application "rc t2" does not work > anymore and > > building "expr" take 30s, and even worse "rc rs expr" takes almost 100s > (result > > is wrong due to failing of "rc"). > > > > I had a look at the diff on github but got no clue where it might come > from. > > You will certainly find it in no time. > > Kurt > > > > > > Am 05.02.2017 um 05:05 schrieb Bill Page: > >> The reason that i wrote this as _rule is because the interpreter seems > >> to have a bug that coerces things to Expression Integer. Using the > >> function call syntax seems to get around that and I also use a package > >> call in order to be very specific if necessary. > > > > -- > > You received this message because you are subscribed to the Google > Groups "FriCAS - computer algebra system" group. > > To unsubscribe from this group and stop receiving emails from it, send > an email to fricas-devel...@googlegroups.com <javascript:>. > > To post to this group, send email to fricas...@googlegroups.com > <javascript:>. > > Visit this group at https://groups.google.com/group/fricas-devel. > > For more options, visit https://groups.google.com/d/optout. > -- You received this message because you are subscribed to the Google Groups "FriCAS - computer algebra system" group. To unsubscribe from this group and stop receiving emails from it, send an email to fricas-devel+unsubscr...@googlegroups.com. To post to this group, send email to fricas-devel@googlegroups.com. Visit this group at https://groups.google.com/group/fricas-devel. For more options, visit https://groups.google.com/d/optout.
