oma is normally in the accusative case (which appears as either the nominative or genitive case depending on the context), but is inflected in the partitive case to express an ongoing or incomplete action or if used in the negative. The same also applies to osuutensa, which also takes a possessive suffix:
possessor
singular
plural
1st person
osuuteni
osuutemme
2nd person
osuutesi
osuutenne
3rd person
osuutensa
In negative (e.g. ei tehnyt omaa osuuttaan(“did not do his/her [own] part”)), the last word is inflected in possessive forms as follows:
