SUR UN THÉORÈME DE GÉOMÉTRIE SPHÉRIQUE: THÉODOSE, MÉNÉLAÜS, IBN ˓ IRĀQ ET IBN HŪD.

In his encyclopedic book (al-Istikmāl), the mathematician of Saragossa, Ibn Hūd (d. 1085/478 H.), established by an intrinsic demonstration of spherical geometry, a remarkable theorem which generalizes the proposition III.11 from Theodosius's Spherics and integrates the propositions III.23-25 from Menelaus's Spherics. In this paper, we study this theorem and the demonstration of Ibn Hūd. The reader will find also some established and translated texts (Ibn Hūd, Ibn Irāq, al-Ṭūsī) addressing the same theme. [ABSTRACT FROM AUTHOR]