July 18, 2008

RTA 2008

I am just back from the RTA 2008 (Rewriting Techniques and Applications) conference in Linz. My talk has been on Wednesday and was about Functional-logic Graph Parser Combinators. I already have written on this blog about graph parser combinators, but this purely functional approach had several problems we solved using functional-logic programming techniques. In particular, the new framework can be used as a back-end for my approach to diagram completion.

Hagenberg, the conference location, is a nice little village 20km away from Linz. It has a romantic, medieval castle in which the conference took place. Furthermore, an important branch of the FH Oberösterreich is located here.

From the talks I attended I especially liked the invited one by Thomas Hillenbrand about the theorem prover Waldmeister which is known to be very fast and powerful. Recently, the popular computer algebra system Mathematica even incorporated the Waldmeister approach to equational theorem proving into its tool suite.

Although I do not know much about automatic theorem proving there have been some impressive facts I remember from the talk. First of all, it is still very important to think about the most efficient data structures for a particular application. In theorem proving execution time and memory usage are really a big issue, so every little improvement of the data structures might make a decisive difference. And second, there is no all-in-one algorithm suitable for every application domain. Thus, it is important to provide a flexible framework that can be parameterized by the users. In Waldmeister one has to choose among several weighting functions from which each one is superior for some special domains. Finally, automatic theorem proving has advanced a lot in the last years. Even for some "real proofs" there is a good chance that they can be found without much manual investigation.

No comments: