Abu Sahl al-Quhi

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Abu Sahl Waidschan ibn Rustam al-Quhi , also al-Kuhi ( Arabic أبو سهل ويجن بن رستم القوهي, DMG Abū Sahl Waiǧan b. Rustam al-Qūhī ; Persian ابوسهل بیژن کوهی, DMG Abū-Sahl Bīžan Kūhī ; * around 940 from Quh in Tabaristan , Iran ; † around 1000 ) was a Persian astronomer and mathematician.

Along with Abu al-Wafa and al-Sidschzi, Al-Quhi was an important astronomer and mathematician who lived at their court in Baghdad when the Buyid dynasty came to power . In 969/970 he made observations of the winter and summer solstices in Shiraz with al-Sidschzi and others on the orders of the caliph Adud ad-Daula . He was also at court in Baghdad under the successor caliph Sharaf ad-Daula (who ruled from 983) and, on the orders of the caliph, made planetary observations in a newly built observatory (which was inaugurated in 988) in the palace garden of the caliph in Baghdad. Only a year later, the observatory closed with the death of the caliph, which ushered in a period of decline for the dynasty.

The perfect compass

Al-Quhi is best known for his work in geometry , in which he continued the tradition of the ancient Greek mathematicians, alongside Euclid, among others, Apollonius and Archimedes . For example, he solved a problem similar to the problems posed by Archimedes in his treatise on spheres and cylinders: for given spherical segments A, B find a spherical segment with the same volume as B and the same area as A. The solution uses the intersection of a hyperbola with a parabola . He also completed the construction of the regular heptagon in an Arabic treatise going back to Archimedes. Another problem he solved was inscribing an equilateral pentagon in a square, which leads to the solution of a fourth degree equation. He also wrote a treatise on the astrolabe , in which he solved some difficult imaging problems, and a treatise on the perfect compass , a device for constructing conic sections with application to the construction of astrolabes and sundials .

Correspondence with the high-ranking official Abu Ishaq as-Sabi , who was interested in mathematics, has also been received from al-Quhi .

literature

  • Yvonne Dold-Samplonius : Article Al-Quhi in Dictionary of Scientific Biography
  • Moritz Steinschneider : Lettere intorno ad Alcuhi a D. Bald. Boncompagni , Rome, 1863
  • Heinrich Suter : The mathematicians and astronomers of the Arabs , 1900
  • Jan Hogendijk : Two beautiful geometrical theorems by Abu Sahl Kuhi in a 17th century Dutch translation , Ta'rikh-e Elm: Iranian Journal for the History of Science 6 (2008), 1–36
  • John Lennart Berggren , Jan Pieter Hogendijk: The Fragments of Abu Sahl al-Kuhi's Lost Geometrical Works in the Writings of al-Sijzi , in: C. Burnett, JP Hogendijk, K. Plofker, M. Yano (editors): Studies in the History of the Exact Sciences in Honor of David Pingree , Leiden: Brill, 2003, pp. 605-665

Web links

Individual evidence

  1. ↑ John Lennart Berggren : al-Kuhi's Filling a lacuna in Book II of Archimedes in the version of Nasir al-Din al-Tusi , Centaurus, Volume 38, 1996, pages 140-207
  2. ↑ For example J. Berggren Episodes in the Mathematics of Medieval Islam , Springer Verlag 1986, p. 78f
  3. ^ J. Hogendijk: al-Kuhi's construction of an equilateral pentagon in a given square , Zeitschrift für Gesch. Arab-Islam. Wiss., Volume 1, 1984, pages 100-144, correction and supplementation Volume 4, 1986/87, p. 267
  4. ↑ Berggren: The correspondence of Abu Sahl al-Kuhi and Abu Ishaq al-Sabi: a translation with commentaries (Arabic with English translation), J. Hist. Arabic Sci., Vol. 7, 1983, pp. 39-124.
personal data
SURNAME Quhi, Abu Sahl al-
ALTERNATIVE NAMES Quhi, Abu Sahl Waidschan ibn Rustam al- (full name); Kuhi, Abu Sahl al
BRIEF DESCRIPTION Persian mathematician and astronomer
DATE OF BIRTH around 940
PLACE OF BIRTH Quh, Tabaristan , Iran
DATE OF DEATH around 1000