Monday, April 27, 2026

Top Italian Mathematicians

 



  1. Fibonacci (Leonardo of Pisa, c. 1170–1240)
    Often regarded as the most influential medieval European mathematician. He introduced the Hindu-Arabic numeral system (including zero) to the Western world in his book Liber Abaci, revolutionizing commerce, science, and calculation. He is best known for the Fibonacci sequence (0, 1, 1, 2, 3, 5, 8, ...), which appears in nature, art, and modern applications like computer algorithms and biology.
    Also see: Fibonacci Day, Speed Limits, The Creator
    (Image: By Hans-Peter Postel - Own work, CC BY 2.5, https://commons.wikimedia.org/w/index.php?curid=1739679)




  2. Joseph-Louis Lagrange (Giuseppe Luigi Lagrangia, 1736–1813)
    A towering figure in mathematical analysis, celestial mechanics, and number theory. Born in Turin (then part of the Kingdom of Sardinia), he worked extensively in France and is considered one of the greatest mathematicians of the 18th century. Key contributions include Lagrangian mechanics (foundational to classical physics), the Lagrange multiplier method in optimization, and major advances in algebra and the calculus of variations. He is frequently ranked among the top Italians in historical popularity indices.
    (Image: Public Domain - https://commons.wikimedia.org/wiki/File:Lagrange_crop.jpg)

  3. Gerolamo Cardano (1501–1576)
    A Renaissance polymath whose Ars Magna (1545) was the first major Latin treatise on algebra, introducing solutions to cubic and quartic equations (building on earlier Italian work by del Ferro, Tartaglia, and Ferrari). He also made pioneering contributions to probability theory and is noted for his broad influence on mathematics, medicine, and philosophy during the Italian Renaissance.
    (Image: Ginko Edizioni)


  4. Galileo Galilei (1564–1642)
    While primarily remembered as a physicist and astronomer, Galileo was a profound mathematician who applied rigorous mathematical methods to the study of motion, falling bodies, and kinematics—laying groundwork for modern physics and the scientific method. His work on geometry, proportions, and experimental mathematics bridged the Renaissance and the Scientific Revolution. Many lists of great Italian mathematicians include him for his mathematical innovations in mechanics.
    (Image: Public Domain - https://en.wikipedia.org/wiki/Galileo_Galilei#/media/File:Galileo_Galilei_(1564-1642)_RMG_BHC2700.tiff)


  5. Vito Volterra (1860–1940) 
    Vito Volterra is renowned for his work in functional analysis (integral equations, Volterra operators) and mathematical biology (predator-prey models, now foundational in ecology).

    (Image: By Unknown author - http://www.phys.uniroma1.it/DipWeb/dottorato/SCUO_VOLTERRA/scuola_volterra.html, Public Domain, https://commons.wikimedia.org/w/index.php?curid=16117839 )

Other Notable Mentions

  • Luca Pacioli (c. 1447–1517): "Father of accounting" and popularizer of double-entry bookkeeping; collaborator with Leonardo da Vinci.
  • Bonaventura Cavalieri and Evangelista Torricelli: 17th-century pioneers in indivisibles and early calculus ideas.
  • Scipione del Ferro, Niccolò Tartaglia, and Lodovico Ferrari: Solved cubic and quartic equations in the Renaissance.
  • Maria Gaetana Agnesi (1718–1799): Early female mathematician known for the "witch of Agnesi" curve and comprehensive calculus text.
  • Gregorio Ricci-Curbastro developed the tensor calculus (with Tullio Levi-Civita), which became essential for Einstein's general relativity and differential geometry. Other strong contenders for this spot include Giuseppe Peano (axiomatization of natural numbers and mathematical logic) and Ennio de Giorgi or Enrico Bombieri (Fields Medalist) for more modern contributions.

Modern-era figures like Enrico Bombieri (Fields Medal 1974) and Eugenio Calabi also rank highly in specialized fields but are less "all-time" dominant than the historical giants. Other current figures include:

  • Alfio Quarteroni (born May 30, 1952, in Ripalta Cremasca, Italy) is a prominent Italian mathematician specializing in numerical analysis, scientific computing, and mathematical modeling.
  • Professor Piergiorgio Odifreddi (born 1950 in Cuneo, Italy) is an Italian mathematician, logician, and popular science writer specializing in mathematical logic, recursion theory (computability theory), and the foundations of mathematics. He is Professor Emeritus of Mathematical Logic at the University of Turin, where he taught for many years, and has held visiting positions at institutions such as Cornell University and the University of California, Berkeley.
  • Professor Roberto Renò (born in Italy) is an Italian mathematician and quantitative finance expert specializing in financial econometrics, volatility modeling, asset pricing, and statistical methods for financial markets. He holds a PhD in Financial Mathematics from the Scuola Normale Superiore in Pisa (2005, magna cum laude) and a degree in Physics from the University of Pisa.

Friday, April 24, 2026

100,000!






This blog recently reached 100,000 views. The number 100,000 is significant in many ways.

  • In South Asia, one hundred thousand is one lakh and is expressed numerically as 1,00,000.
  • Cead Mile Failte is an Irish greeting meaning 100,000 welcomes.
  • 100,000 meters is the altitude considered where space flight begins.
  • 104,723 and 104,729 are the 9999th and 10,000th prime numbers (by the prime number theorem, the frequency of prime numbers decreases as numbers increase - it makes it easy to remember that the frequency is 1/10 at 100,000).
  • In the Netherlands, 100,000 is informally called a ton.
  • More interesting facts about 100,000 at: https://en.wikipedia.org/wiki/100,000 


Sunday, March 29, 2026

A392975 - A contribution to the On-Line Encyclopedia of Integer Sequences (OEIS)

 

(Image: Michael De Vlieger)

I recently proposed a new sequence for the On-Line Encyclopedia of Integer Sequences (OEIS). 

A Sisyphus sequence: a(0) = 0, a(1) = 1, a(2) = 2; for n > 2, a(n) is the smallest unused positive integer having the same greatest prime factor as the sum of the previous terms.

Sisyphus is a figure in Greek mythology, known as the cunning King of Corinth who was punished by Zeus to eternally roll a massive boulder up a hill in Tartarus, only for it to roll back down each time. Numerical sequences are sometimes called Sisyphus sequences when their terms climb and climb, but then drop repeatedly. 

The image above shows this process for this sequence for the first 10^6 terms. Below is a graph for how the sequence begins (first 300 terms):

One interesting feature of the sequence is the low points all appear to be prime. They begin:  7, 13, 17, 19, 23, 29, 59, 107, 137, 173, 257, 293, 467, 503...
This trend continues for at least the first 200,000 terms of the sequence.

Another feature of the sequence is that beginning with the third term, the common greatest prime factor repeats in runs of 3 or more. These factors begin:  3, 3, 3, 7, 7, 7, 7, 13, 13, 13, 13... and this trend continues for at least the first 200,000 terms of the sequence.

The proposed sequence is currently in draft form in the OEIS: https://oeis.org/draft/A392975.

(Image: Sisyphus (1548–49) by Titian, Prado Museum, Madrid, Spain)

Update 4/3/2026: the sequence was published A392975 - OEIS https://share.google/xGszszi55zd2fat2g. 

Update 4/14/2026: a companion sequence, A396326, was published: Low points in A392975 (having the property of being all prime numbers).

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