Hi Friam, Returning from music to the question of searching for mathematical expressions. This may be foolish, but what about using a functional programming language, such as Haskell, as a "standard format" for searchable math expressions? It reads enough like math that it wouldn't be very difficult to learn, and the context of an executable code ensures a form of validity testing by the person initiating the query (make sure it evaluates correctly on your own machine, then submit the code as a search string). It wouldn't be necessary that a search engine support all forms of representation initially; it would be enough to support one form in a useful way.
I want to imagine, though this is not well thought out, that one wants a definitional language rather than an assignment language, even if evaluating the expression on some standard set of inputs would be one criterion for assigning it a mathematical "identity". Even better, of course, would be to have criteria for a "normal form" of some kind, so that among the possible changes of variable in a single equation, automatic conversions could select a particular one as the search standard. This would be along the lines of using a symbolic package as an engine to try to relate different representations of equivalent expressions. Does this add anything to what can be done now? Eric ============================================================ FRIAM Applied Complexity Group listserv Meets Fridays 9a-11:30 at cafe at St. John's College lectures, archives, unsubscribe, maps at http://www.friam.org
