# Al-Nayrizi

**Abū’l-‘Abbās al-Faḍl ibn Ḥātim al-Nairīzī** (Arabic: أبو العباس الفضل بن حاتم النيريزي, Latin: *Anaritius, Nazirius*, 865–922) was a Persian^{[1]} mathematician and astronomer from Nayriz, Fars Province, Iran.

He flourished under al-Mu'tadid, Caliph from 892 to 902, and compiled astronomical tables, writing a book for al-Mu'tadid on atmospheric phenomena.

Nayrizi wrote commentaries on Ptolemy and Euclid. The latter were translated by Gerard of Cremona. Nairizi used the so-called umbra (versa), the equivalent to the tangent, as a genuine trigonometric line (but he was anticipated in this by al-Marwazi).

He wrote a treatise on the spherical astrolabe, which is very elaborate and seems to be the best Persian work on the subject. It is divided into four books:

- Historical and critical introduction.
- Description of the spherical astrolabe; its superiority over plane astrolabes and all other astronomical instruments.
- Applications.
- Applications.

He gave a proof of the Pythagorean theorem using the Pythagorean tiling.^{[2]}

Ibn al-Nadim mentions Nayrizi as a distinguished astronomer with eight works by him listed in his book *al-Fihrist*.

## NotesEdit

**^**Hamilton Alexander Rosskeen Gibb (1993).*The Encyclopaedia of Islam: MIF-NAZ*. Brill. p. 1050.AL-NAYRIZI, ABU 'L-CABBAS AL-FADL B. HATIM, Persian geometer and astronomer

**^**Nelsen, Roger B. (November 2003), "Paintings, plane tilings, and proofs" (PDF),*Math Horizons*: 5–8. Reprinted in Haunsperger, Deanna; Kennedy, Stephen (2007),*The Edge of the Universe: Celebrating Ten Years of Math Horizons*, Spectrum Series, Mathematical Association of America, pp. 295–298, ISBN 978-0-88385-555-3. See also Alsina, Claudi; Nelsen, Roger B. (2010),*Charming proofs: a journey into elegant mathematics*, Dolciani mathematical expositions,**42**, Mathematical Association of America, pp. 168–169, ISBN 978-0-88385-348-1. Nelsen uses the "Annairizi" form of his name; for the identification of it with Anaritius, see*Isis*, vol. 6, p. 515.

## ReferencesEdit

- H. Suter: Die Mathematiker und Astronomen der Araber (45, 1900)
- Nachtrage (164, 1902).
- O'Connor, John J.; Robertson, Edmund F., "Abu'l Abbas al-Fadl ibn Hatim Al-Nayrizi",
*MacTutor History of Mathematics archive*, University of St Andrews.

## Primary sourcesEdit

## External linksEdit

- Sabra, A. I. (2008) [1970-80]. "Al-Nayrīzī, Abu'l-'Abbās Al-Faḍl Ibn Ḥātim".
*Complete Dictionary of Scientific Biography*. Encyclopedia.com. - DeYoung, Gregg (2007). "Nayrīzī: Abū al‐ʿAbbās al‐Faḍl ibn Ḥātim al‐Nayrīzī". In Thomas Hockey; et al. (eds.).
*The Biographical Encyclopedia of Astronomers*. New York: Springer. p. 823. ISBN 978-0-387-31022-0. (PDF version)

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