In the ALEXANDROS TO HELLENIKON PAIDION book, at p.189, it is written :
Ἡ σύναρθρος ἀντωνυμία· τῇ συνάρθῳ ἀντωνυμίᾳ χρῶνται καὶ τὰς τῆς ἀντωνυμίας γενικὰς καὶ τάσδε· ἐμός, σός, ἡμέτερος, ὑμέτερος·
The pronoun accompanied by the article: with the pronoun accompanied by the article they treat both the genitives of the pronoun and these: my, thy, our, your.
I think I must be missing something. Thanks!