12th-century Muslim scholar and mathematician of Morocco
Al-Hassar orAbu Bakr Muhammad ibn Abdallah ibn Ayyash al-Hassar (Arabic:أبو بكر محمد ابن عياش الحصَار) was a 12th-centuryMoroccanmathematician. He is the author of two booksKitab al-bayan wat-tadhkar (Book of Demonstration and Memorization), a manual of calculation andKitab al-kamil fi sinaat al-adad (Complete Book on the Art of Numbers), on the breakdown of numbers. The first book is lost and only a part of the second book remains.[1]
Al-Hassar developed the modern symbolicmathematical notation forfractions, where thenumerator anddenominator are separated by a horizontal bar. This same fractional notation appeared soon after in the work ofFibonacci in the 13th century.
^Selin, Helaine, ed. (1997).Encyclopaedia of the history of science, technology, and medicine in non western cultures. Boston: Kluwer Academic. p. 615.ISBN0-7923-4066-3.
Suter, Heinrich,Beitraege zur Geschichte der Mathematik und Astronomie im Islam. Nachdruck seiner Schriften aus den Jahren 1892-1922. [Contributions to the history of mathematics and astronomy in Islam. Reprint of his works from the years 1892-1922]. Hrsg. von Fuat Sezgin. Baende 1 und 2. [Ed. by Fuat Sezgin. Volumes 1 and 2] Veroeffentlichungen des Institutes fuer Geschichte der Arabisch-Islamischen Wissenschaften. Reihe B: Nachdrucke, Abteilung Mathematik, Bd. 1 [Publications of the Institute for the History of Arabic-Islamic Sciences. Series B: Section Mathematics, vol. 1] Frankfurt am Main: Institut fuer Geschichte der Arabisch- Islamischen Wissenschaften an der Johann Wolfgang Goethe-Universitaet, 1986. Band I: xiii, 761 S.; Band II: x, 724 S.
Aballagh, M.; Djebbar, A. (1987). "Découverte d'un écrit mathématique d'al-Hassar (XIIe s.): Le livre I du Kamil".Historia Mathematica.14 (2):147–158.doi:10.1016/0315-0860(87)90018-8.ISSN0315-0860.
