Privet Sébastien, Thanks for reply,
> We are thinking of many new functionalities to add in the Words > library. Some of them are related to automata and languages. For > example, I was thinking to add a class for Language. For example, one > could create a finite language from Words like : > > Also, it could be interesting to create a Language from an automata. > So, these are my related thougths. Seems nice! We probably should design a generic Language class which `knows' of itself, whether it is finite, or derived from known automata, or grammar, or regexp, whatever. Operations on languages are to be implemented, again with respect to underlying descriptions, calling apropriate functions for them. Having implemented conversion algorithms (automata <--> grammars etc) language could convert its description internally, when told explicitly or during some self- optimization. BTW, there is a question of basics: how to represent unknown/ uncomputable. Say, you are going to intersect two unrestricted context- free languages (each having a pushdown automaton or a grammar inside). As far as this is generally unsolvable, you should get either UNKNOWN or CHAOS value (if we ever turn to threefold true-false-chaos logic, I'm totally unaware of Python and Sage in this respect), or get a kind of UnsolvableException. In any case, we should represent these cases in a consistent way. It may have sense to represent higher-complexity languages (context- sensitive and above, or as well those having just big description size) using finite `precision', like being `approximated' by finite langage of words with length < n. This will give possibility to solve problems `approximately', which may turn useful to quickly check some properties among limited set of specimen and find early clues and informative examples. Again, after all, reducing traditional whiteboard handwork. vsego dobrogo, --Pavel. --~--~---------~--~----~------------~-------~--~----~ 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 -~----------~----~----~----~------~----~------~--~---
