**Annibale Comessatti** was an Italian mathematician who worked in in algebraic geometry.

- Annibale attended the classical school in Udine and graduated with his baccalaureate in 1904.
- Comessatti began publishing articles quite early on in his university career: Una dimostrazione della formula di Meissel Ⓣ(A demonstration of the formula of Meissel) (1906), Di una generazione del complesso tetraedrale Ⓣ(On a tetrahedral complex generation) (1907) and Sulla dispersione dell' energia nel campo elettromagnetico generato dalla convenzione di una o due cariche Ⓣ(On the dispersal of energy in the electromagnetic field generated by the group of one or two charges) (1908).
- In 1908, after graduating, Comessatti was appointed as Severi's assistant at the University of Padua.
- ideas introduced by Comessatti in the fundamental papers 'Fondamenti per la geometria sopra le superficie razionali dal punto di vista reale' Ⓣ(Basics of the geometry of the rational surface from the real point of view) (1912), and 'Sulla connessione delle superficie razionali reali' Ⓣ(On the connection of the real rational surface) (1914) can be applied to get a classification of real del Pezzo surfaces in an elementary and unitary way by using projective methods and ...
- Comessatti's point of view was essentially birational ...
- In 1914 Comessatti was given the title of lecturer in Descriptive Geometry after writing twelve papers in the six years following the publication of his thesis.
- In July 1915 Comessatti was called up for military service and spent most of the war years in the zone where fighting was most intense.
- Comessatti was awarded two military crosses for bravery for his service during World War I.
- One of his best students at Padua was Ugo Morin who, after studying with Comessatti, graduated in 1926 and then served as Comessatti's assistant at Padua.
- In 1930, Comessatti published the first of two volumes of his textbook Lezioni di Geometria Analitica e Proiettiva Ⓣ(Lessons on analytic and projective geometry).
- The work is written in the peculiar limpid style of Comessatti, and is printed on thin opaque paper, making a convenient volume.
- The second of the two volumes was published in 1931 and Comessatti later prepared a second edition which appeared in 1941 (Volume 1) and 1942 (Volume 2).
- Annibale Comessatti was president of the Mathematics Section.
- Several of the mathematicians at Padua were very active opponents of Fascism, including Ugo Morin, Comessatti's student and later his assistant.
- In 1943 Comessatti published the survey article Problemi di realtà per le superficie e varietà algebriche Ⓣ(Existence problems for surface and algebraic varieties) which looked at properties of algebraic varieties over the real field, regarded as constructs on the similarly defined varieties over the complex field.
- The paper contains a summary of Comessatti's long list of results for rational surfaces.
- This tragic loss hastened a decline in Comessatti's health but he was determined to continue teaching and, after he became so ill that he could not go to the university, he still had students come to his home for lessons.
- After his death he is remembered with the naming a road in Udine the Via Annibale Comessatti.
- On 26 April 1947 a commemoration of Comessatti's life and work was held in the University of Padua.
- The affection for Comessatti was shown by the many friends, alumni and students from the University of Padua who attended.

Born 30 January 1886, Udine, Austrian Empire (now Italy). Died 13 September 1945, Padua, Italy.

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Origin Italy

**O’Connor, John J; Robertson, Edmund F**: MacTutor History of Mathematics Archive