Abū al-Ḥasan ibn ʿAlī ibn
Muḥammad ibn ʿAlī al-Qalaṣādī (Arabic: أبو الحسن علي بن محمد بن علي القرشي البسطي; 1412–1486) was a Muslim Arab mathematician from Al-Andalus specializing
in Islamic inheritance jurisprudence.
Al-Qalaṣādī is known for being one
of the most influential voices in algebraic notation since
antiquity and for taking "the first steps toward the introduction of algebraic symbolism''.
He wrote numerous books on arithmetic and algebra,
including al-Tabsira fi'lm al-hisab (Arabic: التبصير في علم الحساب "Clarification of the science of arithmetic").
Early life
Al-Qalaṣādī was born in Baza, an outpost of the Emirate of
Granada. He received education in Granada, but continued to support his
family in Baza. He published many works and eventually retired to his native
Baza. He spent seven years living in Tlemcen, where he studied under the
local Berber scholars, the most important of which was a man named
Ibn Zaghu.
Map of the coasts of the kingdom of Granada by Piri Reis (16th
century).
His works dealt with Algebra and contained the precise mathematical answers
to problems in everyday life, such as the composition of medicaments, the
calculation of the drop of irrigation canals and the explanation of frauds
linked to instruments of measurement. The second part belongs to the already
ancient tradition of judicial and cultural mathematics and joins a collection
of little arithmetical problems presented in the form of poetical riddles
In 1480 the Christian forces
of Ferdinand and Isabella, "The Catholic Monarchs",
raided and often pillaged the city, al-Qalasādī himself served in the mountain
citadels which were erected in the vicinity of Baza. al-Qalasādī eventually
left his homeland and took refuge with his family in Béja, Tunisia,
where he died in 1486. Baza was eventually besieged by the forces of Ferdinand
and Isabella and its inhabitants sacked.
Symbolic algebra
Like his predecessors al-Qalaṣādī made attempts at creating
an algebraic notation. However, these symbols were not the invention of
al-Qalaṣādī. The same ones had been used by other mathematicians in North
Africa 100 years earlier. Al-Qalaṣādī represented mathematical
symbols using characters from the Arabic alphabet, where:
·
ﻭ (wa) means
"and" for addition (+)
·
ﻻ (illa) means
"less" for subtraction (-)
·
ف (fi) means
"times" for multiplication (*)
·
ع (ala) means
"over" for division (/)
·
ﺝ (j) represents jadah meaning
"root"
·
ﺵ (sh) represents shay meaning
"thing" for a variable (x)
·
ﻡ (m) represents moraba'a for
a square (x2)
·
ﻙ (k) represents moka'ab for
a cube (x3)
·
ﻝ (l) represents ya'adilu for equality (=)
Sumber
Labels:
Mathematician
Thanks for reading Biografi Abū al-Ḥasan ibn ʿAlī al-Qalaṣādī. Please share...!
