Aḥmad al-Karābīsī's commentary on Euclid's ``Elements''. (Q2737629)

By surveying the material quoted in two commentaries of the tenth-century mathematicians Karabisi and Nayrizi on Euclid's \textit{Elements} the author demonstrates beyond any doubt the extent to which the later Hellenistic and Byzantine mathematical sources were available to the mathematicians working in the Islamic civilization. And by comparing the two commentaries together the author managed to demonstrate, sometimes inadvertently, the richness of the historical significance of this literature.NEWLINENEWLINEThe real difficulty remains in the identification of the Greek authors quoted by those commentators whose names have been hopelessly corrupted during the process of their transliteration into Arabic and scribal transmissions of the manuscripts. In this regard, the author makes very little effort, and thus barely makes a dent in the solution of this problem.NEWLINENEWLINEThe more interesting feature of these early Arabic mathematical commentaries is the ease with which they use the earlier Greek material without having to quote it word for word, as can be judged by comparing the quotations with the original Greek sources whenever the latter have survived. This can only mean that the mathematicians working in the Islamic domain were simply using the Greek material for their own purposes rather than trying to preserve it through canonical translation. And this in itself should mean that they had their own ongoing research projects for which the earlier Greek material was found useful.NEWLINENEWLINEOf similar historical importance is the evidence proffered by the commentaries under study about the manner with which the Arabic translators of the Greek texts constructed their translations. In one instance it becomes abundantly clear that the earliest translator of Euclid's \textit{Elements}, al-Hajjaj b. Matar (fl. 830), whose works have survived, albeit in a fragmentary fashion, produced translations of the \textit{Elements} as well as commentaries on it. In some instances he even offered proofs of his own that were apparently different from the original and from the proofs rendered by other translators. Later users of the Eucledian text and commentaries, such as the ones under discussion in this article, did not refrain from combining the wordings of two separate translations or commentaries in order to make their own case clearer.NEWLINENEWLINEAlthough the present reviewer appreciates the difficulties with which the author is faced, and admires her attempts at the solutions, he nevertheless continues to disagree with her on several of her readings of the Arabic texts as reflected in her transcriptions of them.NEWLINENEWLINE Furthermore he takes issue with the author's general intellectual assumptions, when she says: ``Karabisi's commentary as a text worthwhile to be edited and translated into a modern [read: European] language'' (p. 61), assumptions that reveal an old bias that considers Arabic a \textit{dead} language, and European languages as the only ones that could be called ``modern''.NEWLINENEWLINEFor the entire collection see [Zbl 0963.00039].