On Mar 12, 2009, at 2:17 PM, Florent Hivert wrote: >>> The very purpose of the category framework it to declare in a >>> mathematical >>> way, this that have a matematical meaning. In the case of a right >>> action of A >>> on B, on declare that B is a A-RightModule. It is much more >>> informative by all >>> respect than testing if a random element of A accept to be >>> multiplied by a >>> random element of B. >> >> _rmul_ and _lmul_ are only tried if B is an A-module. (We don't (yet) >> have the distinction between right and left modules, this is part of >> where the "try it out" comes into play). > > Thanks for this explanation... Should I understand that once we had > the > correct framework, these are supposed to disappear ?
They won't disappear--the coercion model will simply assume they're implemented and use them without trying them out first. >> However, not all actions are module actions, e.g. a permutation >> acting on an ordered list, or a matrix acting on a quadratic form (to >> take two examples that I've been thinking about lately). > > Permutations acting on lists is not a module structure but this may > fits in a > category of sets with a group acting on (G-set) no-linearity here. > For acting > on plain list, (i.e. data structure I would rather not use "*" do > denote the > operation). BTW, We already have sage: [1,10,100] * 5 [1, 10, 100, 1, 10, 100, 1, 10, 100, 1, 10, 100, 1, 10, 100] (which is to be like Python) so there is some precedent. Perhaps a better example is an element of a galois group acting on a field. - Robert --~--~---------~--~----~------------~-------~--~----~ To post to this group, send email to sage-devel@googlegroups.com To unsubscribe from this group, send email to sage-devel-unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-devel URLs: http://www.sagemath.org -~----------~----~----~----~------~----~------~--~---
