Giacomo Candido (10 July 1871, in Guagnano – 30 December 1941, in

Galatina Galatina ( el, label=Griko, Ας Πέτρο, As Pètro; scn, label=Salentino, San Pietru), known before the unification of Italy as San Pietro in Galatina, is a town and ''comune'' in the Province of Lecce in Apulia, southern Italy. It is situated ...

) was an Italian mathematician and historian of mathematics.

Education and career

In 1897 Candido received his ''Laurea'' (teaching degree) from the

University of Pisa The University of Pisa ( it, Università di Pisa, UniPi), officially founded in 1343, is one of the oldest universities in Europe. History The Origins The University of Pisa was officially founded in 1343, although various scholars place ...

and started to teach mathematics: first, at the Liceo of Galatina, then at the Liceo of Campobasso and from 1927 at the Liceo of Brindisi. He was an editor and contributor for the ''Periodico di Matematica per l'Insegnamento secondario'' and was one of the founders of the journal ''La Matematica elementare'' (an intermediate-level journal for teachers, engineers and students). He was an Invited Speaker of the ICM in 1928 in Bologna and in 1932 in Zürich. In 1934 he founded the

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n branch of ''Mathesis'', an Italian association of mathematics teachers. He is also remembered for his work on the history of mathematics.

Candido's identity

Candido devised his eponymous identity to prove that

(F_n^2 +F_^2 +F_^2 )^2= 2(F_n^4 +F_^4 +F_^4 )

where F_n is the ''n''th

Fibonacci number In mathematics, the Fibonacci numbers, commonly denoted , form a sequence, the Fibonacci sequence, in which each number is the sum of the two preceding ones. The sequence commonly starts from 0 and 1, although some authors start the sequence from ...

.
The identity of Candido is that, for all real numbers x and y,

(x^2 +y^2 +(x+y)^2 )^2= 2(x^4 +y^4 +(x+y)^4 )

It is easy to prove that the identity holds in any

commutative ring In mathematics, a commutative ring is a ring in which the multiplication operation is commutative. The study of commutative rings is called commutative algebra. Complementarily, noncommutative algebra is the study of ring properties that are not sp ...

Selected publications

Sulle funzioni U_n , V_n di Lucas''
in Periodica matematica, anno XVII, 1901–1902 * , Tipografia editrice salentina, 1903
''Su d'un' applicazione delle funzioni U_n , V_n di Lucas''
in Periodica matematica, anno XX, 1904–1905
''Le equazioni reciproche in senso generale''
in Periodico matematica, anno XXI, 1905–1906 * ''Il fondo Palagi-Libri della Biblioteca Moreniana di Firenze'', in ''Atti del II Congresso della Unione Matematica Italiana'', ed. Cremonese, 1941 * ''Sulla mancata pubblicazione nel 1826 della celebre memoria di Abel'', ed. Marra,

, 1942 * ''Conferenze e discorsi'', ed. Marra,

, 1943 * ''Scritti matematici'', ed. Marzocco, Firenze, 1948

References

{{DEFAULTSORT:Candido, Giacomo 1871 births 1941 deaths 19th-century Italian mathematicians 20th-century Italian mathematicians People from the Province of Lecce