Abu-l-Hasan Kushayr ibn Labban ibn Bashahri al-Jili
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Abu-l-Hasan Kushayr ibn Labban ibn Bashahri al-Jili, was a Persian mathematician, geographer, and astronomer from Jilan, a.k.a. Gilan, south of the Caspian Sea, Iran.
His main work was probably done about the beginning of the eleventh century, and seems to have taken an important part in the elaboration of trigonometry. For example, he continued the investigations of Abul Wáfa, and devoted much space to this in his tables, al-zij al-jami wa-l-baligh ("The Comprehensive and Mature Tables"), which were translated into Persian before the end of the century. He wrote also an astrological introduction and an arithmetic treatise (extant to Hebrew).
Most significant is his work on Hindu reckoning being the earliest known work on Arabic arithmetic which deals with Hindu numerals. An earlier text by Abu'l-Wafa on arithmetic did not use Hindu numerals. Kushyar's Principles of Hindu reckoning was written about 1000 AD.