Immediately after he does that, the system parses the documents, applies the stemming algorithm
and the TFIDF formulas and ultimately extracts the most important five key concepts from each file: C11-C15, C21-C25.
33] experimental results show that the suggested hybrid method of statistical and light stemmers is the most suitable stemming algorithm
for Arabic language and gives generalization accuracy of about 98%.
Subsequently, the keywords are obtained by employing the stemming algorithm
that filters the affixes present in the crawled documents.
Porter's stemming algorithm
 was applied to remove prefixes and suffixes to obtain word stems.
After traversing the whole document, identifying its words, omitting its stop-list terms and phrases, and identifying its nouns and verbs, a stemming algorithm
is applied to each word, in the second phase.