Nous avons cherch dcle sur le Livre V des ments d'Euclide, m; et notamment de traduire en anglais les passages que nous avons jug d'expliquer pourquoi certains maths lfinition des grandeurs proportionnelles que l'on trouve au dléments.

Euclid's definition of proportional magnitudes in the Fifth Book of the Elements gave rise to many commentaries. We examine closely two of these commentaries, one by al-Jayy and the other by Saunderson. Both al-Jayy and Saunderson attempted to defend Euclid's definition by making explicit what Euclid had only implied. We show that the two authors explain Euclid's position in a virtually identical manner.

The Andalusian mathematician and astronomer Ibn Mun the celebrated Definition V.5.