**Luigi Cremona** was the originator of graphical statics, the study of forces in equilibrium, using graphical methods. He wrote papers on geometrical transformations, projective geometry and on graphical solutions.

- Political events, however, were to have a major effect on Cremona's life and the first impact came from the revolution of 1848 which attempted to achieve a new and more liberal constitution.
- Cremona, all his life an ardent Italian nationalist, immediately joined the 'Free Italy' battalion.
- Cremona, by this time a sergeant, was with the troops defending Venice.
- Cremona was able to return to Pavia.
- On 9 May 1853 Cremona was awarded his doctorate in civil engineering from the University of Pavia.
- But Austria still controlled the region and this made life hard for Cremona who had fought against the Austrian occupation.
- Cremona was by this time engaged in mathematical research and his first paper appeared in March 1855.
- On 17 January 1857, Cremona was appointed a full teacher at the Ginnasio in Cremona.
- Cremona, the capital of the Cremona region of Lombardy was situated on the north bank of the Po River southeast of Milan.
- Cremona was to remain at the school there for three years and during this time he wrote a number of mathematical articles.
- They are not of great importance except that some of them were examining curves using projective methods, techniques which would be characteristic of Cremona's later important mathematics.
- Cremona was to remain in Bologna until October 1867.
- In Cremona's Complete Works there appear 45 articles which he published while at Bologna.
- Also included are Cremona's important work on transformations of plane curves, which were published during this period in 1863 and 1865.
- It was this work which won him the Steiner Prize for 1866, the prize being awarded jointly to Cremona and Rudolf Sturm.
- Also while at Bologna Cremona developed the theory of birational transformations, later known as Cremona transformations, and wrote a series of papers on twisted cubic surfaces.
- In October 1867, on Brioschi's recommendation, another Royal Decree was issued, this time appointing Cremona to the Polytechnic Institute of Milan.
- Cremona's work in statics is of great importance and gives, in a clearer form, some theorems due to Maxwell.
- In a paper of 1872 Cremona took an idea of Maxwell's on forces in frame structures that had appeared in an engineering journal in 1867 and interpreted Maxwell's notion of reciprocal figures as duality in projective 3-space.
- In November 1877, Cremona was appointed to the chair of higher mathematics at the University of Rome.
- Cremona had a large influence on geometry in Italy.
- Many of Steiner's proofs on synthetic geometry were revised and improved by Cremona.
- Cremona was extremely fair in citing the works of others, something which was not too common among many mathematicians at that time.

Born 7 December 1830, Pavia, Lombardy (now Italy). Died 10 June 1903, Rome, Italy.

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Algebra, Geometry, Origin Italy

**Oâ€™Connor, John J; Robertson, Edmund F**: MacTutor History of Mathematics Archive