Abū al-Ḥasan ibn ʿAlī al-Qalaṣādī

Abū al-Hasan ʿAlī al-Qalasādī , Al-Qualasadi, Al-Qualsadi or al-Quraschi al-Basti ( Arabic أبو الحسن علي القلصادي Abu l-Hasan Ali al-Qalasadi , * 1412 in Baza (then Basta); † 1486 in Béja , Tunisia ) was an Arab mathematician from Spain ( al-Andalus ). He is considered the last known Islamic mathematician from al-Andalus.

Al-Qalasadi left his hometown after the Christian conquest and then traveled the Islamic world. He wrote several books on arithmetic and a book on algebra, a commentary on algebra written in verse by al-Yasminiya (died 1204).

He used symbols in algebraic equations. For mathematical operations he used either short Arabic words or letters, such as the word wa (and) for addition, illā (except) for subtraction, fī (in) for multiplication, ʿalā (over) for division andج / ǧ for root,ش / š for the unknown , ${\ displaystyle x}$ م / m for , ${\ displaystyle x ^ {2}}$ ك / k for . After AS Saidan he had no priority here either. The beginnings of algebraic notation can also be found in al-Marrakuschi . ${\ displaystyle x ^ {3}}$

Al-Qalasadi gave series for example for polygonal numbers and pyramidal numbers and approximation methods for roots. However, these results were already known in the Arab world, some of his results on series, for example, in Yaʿish ibn Ibrahim al-Umawi , as-Samaw'al and Abu Mansur al-Baghdadi .

literature

AS Saidan: Al-Qualasadi (or Al-Qualsadi), Abu 'L-Hasan' Ali Ibn Muhammad Ibn 'Ali , Dictionary of Scientific Biography , Volume 11, pp. 229-230
M. Souissi: L'école mathématique maghrébine: quelques examples de ses travaux et certaines de ses particularités, in: Histoire des mathématiques arabes, Algier, 1988, pp. 9-23.

Web links

John J. O'Connor, Edmund F. Robertson : Abū al-Ḥasan ibn ʿAlī al-Qalaṣādī. In: MacTutor History of Mathematics archive .

Individual evidence

↑ Article Al-Qualasadi in Dict. Sci. Biogr.
↑ AS Saidan quotes Yacub ibn Ayyub from Morocco, who worked around 1350, and Ibn Qunfudh in Algiers, who died in 1407/08 as a forerunner
↑ AS Saidan in the article Al-Qualasadi in the dict. Sci. Biogr. Refers to M. Souissi, University periodical, University of Tunis, 9, 1972, pp. 33–49, as the best biography of the time

personal data
SURNAME	Qalaṣādī, Abū al-Ḥasan ibn ʿAlī al-
BRIEF DESCRIPTION	Arabic mathematician from Spain
DATE OF BIRTH	1412
PLACE OF BIRTH	Baza
DATE OF DEATH	1486
Place of death	Béja

[1] Article Al-Qualasadi in Dict. Sci. Biogr.

[2] AS Saidan quotes Yacub ibn Ayyub from Morocco, who worked around 1350, and Ibn Qunfudh in Algiers, who died in 1407/08 as a forerunner

[3] AS Saidan in the article Al-Qualasadi in the dict. Sci. Biogr. Refers to M. Souissi, University periodical, University of Tunis, 9, 1972, pp. 33–49, as the best biography of the time