Person: Al-Jawhari, al-Abbas ibn Said

Al-Jawhari was an Islamic mathematician whose main work was a commentary on Euclid's Elements.

Al-Jawhari was employed in the service of al-Ma'mun in Baghdad, although we do not know exactly when he began his work there.
Al-Jawhari, although best known as a geometer, made observations in Baghdad from 829 to 830 while working for al-Ma'mun.
The main work by al-Jawhari was Commentary on Euclid's Elements which is listed in the Fihrist (Index), a work compiled by the bookseller Ibn an-Nadim in 988.
Commentary on Euclid's Elements is almost the same work described by Nasir al-din al-Tusi (although al-Tusi gives a slightly different title for al-Jawhari's work: Emendation of the Elements).
This work contained nearly fifty propositions additional to those given by Euclid and included an attempt by al-Jawhari to prove the parallel postulate.
Al-Tusi quotes six of the nearly fifty propositions which together form what al-Jawhari believed was a proof of the parallel postulate.
This means that, as far as we are aware, al-Jawhari was the first Arabic mathematician to attempt such a proof.
In the short treatise al-Jawhari presents three additions to Book V of Euclid's Elements, which are meant prove Definition 5 which defines equal ratio, and Definition 7 which defines greater ratio.
Al-Jawhari's "proofs" are examples of early attempts by Muslim mathematicians to understand the difficult concepts in Euclid's Elements.

Born about 800, possibly Baghdad, Iraq. Died about 860, possibly Baghdad, Iraq.

View full biography at MacTutor

Ancient Arab, Origin Iraq

Epochs: 1

Thank you to the contributors under CC BY-SA 4.0!

O’Connor, John J; Robertson, Edmund F: MacTutor History of Mathematics Archive