Today, 23 November, is Fibonacci day, an occasion to remember one of the most influential mathematicians of the Middle Ages, Leonardo Bonacci, but also and above all a precious opportunity to discover the absolutely wonderful and often unknown relationship between numbers, shapes, nature and proportions.
We have included it in our AGRO mural precisely to emphasise the importance of numbers in nature.
Leonardo Pisano, known as Fibonacci born in Pisa in 1170 and died in 1242 (so called because he was the son of the Bonacci family, his father was Guglielmo Bonacci) was a great mathematician, but also a traveller who, thanks to his contacts with the Arab world, introduced cultural elements of enormous importance that changed the culture of Europe and the western world.
23 November was chosen because in the Anglo-Saxon world the date 11/23 makes up the first four numbers of the Fibonacci succession (also known as the Golden Succession) in which each number is the sum of the previous two:
Fibonacci studied in Algeria (in the city of Bugia near Algiers) and learnt the Indo-Arabic numeral system, which corresponds to today's decimal numeral system, based on the ten digits from 0 to 9, which we still use in mathematics worldwide today. The Indo-Arabic decimal system was more practical in business management and for counting than the Roman numerical system.
Fibonacci also had excellent relations with Emperor Frederick II of Swabia, ruler of Sicily, who between 1230 and 1250 founded the famous Sicilian School, a cultural centre of considerable importance in the Mediterranean. As an enlightened emperor that he was, Frederick II maintained excellent diplomatic relations and cultural exchanges with the Sultan al-Kamil and the Arab world. Moreover, he was passionate about science and mathematics, as well as art and poetry.
Fibonacci contributed decisively to the spread of Arabic mathematics throughout Europe and the western world.
In his most famous work, the 'Liber Abaci' ('book of calculus', from the Latin 'abacus'), published in 1202, Fibonacci introduced the decimal number system (which he called 'Modus Indorum') and the algorithms for performing the four operations in this system, which we still learn in our schooling today.
The Fibonacci sequence in nature
The Fibonacci sequence has also been observed in areas that have little or nothing to do with mathematics. All those in which growth episodes occur, for example, seem to be affected by this particular series.
Two examples out of all:
- The arrangement of leaves along the branch of a plant;
- The spiral distribution of the floscules of daisies and sunflower seeds.
Looking at the number of repeating elements, one generally finds repeated Fibonacci numbers: 21 and 34 in daisies, 34 and 55 in sunflowers, 5 and 8 in the spiral series of pine cones, 8 and 13 in pineapples, and so on.
Source: Fibonacci Day, il 23 novembre si celebra il grande matematico italiano - Libreriamo
