Abu Bakr al-Hassar
{{Short description|12th-century Muslim scholar and mathematician of Morocco}}
Al-Hassar or Abu Bakr Muhammad ibn Abdallah ibn Ayyash al-Hassar ({{langx|ar|أبو بكر محمد ابن عياش الحصَار}}) was a 12th-century Moroccan mathematician. He is the author of two books Kitab al-bayan wat-tadhkar (Book of Demonstration and Memorization), a manual of calculation and Kitab 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.{{cite book |editor-first=Helaine |editor-last=Selin |editor-link=Helaine Selin |title=Encyclopaedia of the history of science, technology, and medicine in non western cultures |location=Boston |publisher=Kluwer Academic |year=1997 |page=615 |isbn=0-7923-4066-3 }}
Al-Hassar developed the modern symbolic mathematical notation for fractions, where the numerator and denominator are separated by a horizontal bar. This same fractional notation appeared soon after in the work of Fibonacci in the 13th century.
References
Further reading
- 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.
- {{cite journal |last=Aballagh |first=M. |last2=Djebbar |first2=A. |title=Découverte d'un écrit mathématique d'al-Hassar (XIIe s.): Le livre I du Kamil |journal=Historia Mathematica |volume=14 |issue=2 |pages=147–158 |year=1987 |issn=0315-0860 |doi=10.1016/0315-0860(87)90018-8|doi-access= }}
External links
- Prof. Paul Kunitzsch, Al-Hassâr's Kitâb al-Bayân and the Transmission of the Hindu-Arabic Numerals [http://www.muslimheritage.com/day_life/default.cfm?ArticleID=705&Oldpage=3] retrieved 01-09-2010)
- Manuscript of Kitâb al-bayân wa-l-tadhkâr, online by Library of the University of Pennsylvania, Philadelphia [http://sceti.library.upenn.edu/sceti/ljs/PageLevel/index.cfm?ManID=ljs293&Page=1] (retrieved 01-09-2010)
{{authority control}}
{{DEFAULTSORT:Hassar, Abubakr}}
Category:Medieval Moroccan mathematicians
Category:12th-century mathematicians
Category:Year of death unknown