Development of a Stemmer for the Greek Language - SAIS

But it is not the same for the verbs. Every verb has two stems for each voice
(passive and active); the “present stem” and the “past stem”. The tenses are
formed according to these stems. Moreover, the verbs starting with a consonant
take the letter “ε” in some of the past tenses. The various formations of the verb
“∆ΕΝΩ” (tide) presented on the Table 5.
Tenses Verb Stems Suffixes
∆ΕΝΩ
(I tide)
∆ΕΝ Ω
ΘΑ ∆ΕΝΩ ∆ΕΝ Ω
Present Tenses (I will be tiding)
∆ΕΝΕ
(tide)
∆ΕΝ Ε
∆ΕΝΟΝΤΑΣ
(tiding)
∆ΕΝ ΟΝΤΑΣ
Ε∆ΕΣΑ
(I tided)
∆ΕΣ Α
ΝΑ ∆ΕΣΩ
(to tide)
∆ΕΣ Ω
Past Tenses ΝΑ ∆ΕΣΩ
(to tide)
∆ΕΣ Ω
∆ΕΣΕ
(tide)
∆ΕΣ Ε
∆ΕΣΕΙ
(I have tide)
∆ΕΣ ΕΙ
Table 5: Different stems of verbs
2.6 Agreements for the Greek Stemmer
Before we continue with the presentation of the stemming algorithm it is
important to note the agreements that took place during this stemmer development.
As the Greek language is highly inflectional, the suffix removal process could be
very time-consuming and the algorithm could be very complicated using long
corpus and many exceptions. On the other hand, if we have too general rules we
may reduce two semantically different words to the same root (overstemming).
The algorithm works for the Greek words in capital letters as we mentioned in the
paragraph 1.6 on the limitations of the system. Using characters in upper case we
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