Arabic stemming without a root dictionary

We have implemented a root-extraction stemmer for Arabic which is similar to the Khoja stemmer but without a root dictionary. Our stemmer was found to perform equivalently to the Khoja stemmer as well as so-called "light" stemmers in monolingual document retrieval tasks performed on the Arabic Trec-2001 collection. A root dictionary, therefore, does not improve Arabic monolingual document retrieval.