Keywords

1 Introduction

Fabio Conforto gave a lot to his students, university, and science, with his deep and many-sided work in the most different fields of scientific research and teaching.Footnote 1

Fabio Conforto has been one of the most relevant figures of the Italian mathematical landscape in the difficult historical period that goes from the 1930s to the beginning of the 1950s of the twentieth century. Besides the educational activity inside the University of Rome, Conforto carried out a significant research activity in the field of algebraic geometry but also of the study of applied mathematics. He was in fact one of the collaborators of Mauro Picone (1885–1977) at the National Institute for the Applications of Calculus (Istituto Nazionale per le Applicazioni del Calcolo, from now on INAC) and one of the professors of the National Institute of Higher Mathematics (Istituto Nazionale di Alta Matematica, from now on INdAM), managed by Francesco Severi (1879–1961). During his life, Conforto collected a wide selection of books and scientific papers that ranged from pure to applied mathematics, without neglecting works about logics, philosophy, and foundations. Conforto’s collection of books and papers reflects his multiple interests and represents a useful instrument for reconstructing his scientific biography.Footnote 2 In this work, we are going to point out the most relevant events of Conforto’ short but intense academic career in Rome.

2 Early Career of Conforto

Fabio Conforto was born on 13 August 1909 in Trieste, which at that time was part of the Austro-Hungary Empire. Soon after his birth, his family moved to Vienna. Conforto’s parents were Italian speaking, so at home, the young Fabio spoke Italian. When he began attending elementary school, he learnt to speak, read, and write in German. His bilingualism would be very useful for Conforto after some years.Footnote 3

Conforto spent the first 10 years of his life in Vienna. After the end of WWI, Conforto’s family returned to Trieste, where Fabio completed his secondary education. He attended the Gymnasium, and then he completed his schooling at scientific high school (Liceo Scientifico), undertaking the work of the final 2 years in a single year and taking the State Examination 1 year early.

In 1926, Conforto entered the Faculty of Engineering at the Polytechnic University of Milan. Oscar Chisini, who was one of his teachers at the Polytechnic, immediately recognized Conforto’s mathematical inclination and suggested him to devote himself to pure mathematics, instead of practical applications.Footnote 4 So Conforto was discharged from the Milan Polytechnic in order to go to the University of Rome, and in the autumn of 1928, he and his family moved to Rome, which was going to become his second “native land.”Footnote 5

3 Fabio Conforto in Rome

When Conforto arrived in Rome, the city was one of the most important centers as regards mathematics. Thanks to the presence of mathematicians like Guido Castelnuovo (1865–1952), Federigo Enriques (1871–1946), Vito Volterra (1860–1940), and Tullio Levi-Civita (1873–1941), the program of the so-called Rome of scientists—conceived since 1870 by Luigi Cremona (1830–1903) and Quintino Sella (1827–1884)—was going to be pursued, despite the difficulties. Castelnuovo was called to Rome in 1891 to become full professor. At the beginning of his Roman period, he met Enriques, who had just graduated at the Scuola Normale Superiore in Pisa and had moved to Rome to attend Cremona’s courses. Castelnuovo oriented Enriques’ study toward algebraic surfaces.Footnote 6 After the end of WWI, the Italian school of algebraic geometry was growing, and Rome represented the main site.Footnote 7 Besides Castelnuovo, the leading representatives were Enriques and Severi, who were called to Rome in 1921.Footnote 8

Conforto’s scientific education was carried out in Rome since the end of the 1920s. In the autumn of 1928, Conforto entered the University of Rome where he attended lectures by Tullio Levi-Civita, Guido Castelnuovo, and Federigo Enriques. Conforto was particularly influenced by the lectures of higher mechanics of Vito Volterra.

Following Volterra’s theories, Conforto’s first works, appeared in 1930 and 1931, dealt with absolute differential calculus in a continuous function space. The three works, prepared under Volterra’s guidance, were presented by Volterra in the reports of the Accademia dei Lincei.Footnote 9 In the period July–September 1930 and 1931, Conforto attended the cadet school in the city of Lucca. Here he met the physicist Gilberto Bernardini (1906–1995), who was assistant of Giuseppe Occhialini (1907–1993) in the chair of physics at the University of Florence. Conforto graduated in pure mathematics at the University of Rome summa cum laude on 3 July 1931.Footnote 10

Soon after the degree, Conforto obtained a scholarship of £8000, supported by the National Research Council, in order to spend a period of study at the University of Göttingen, in Germany. Conforto stayed in Göttingen from January to June 1932. Thanks to his bilingualism (Italian and German), he could benefit and be influenced by two different mathematical ways of study.Footnote 11 In Göttingen, Conforto could deepen his research in the field of geometry in a continuous function space. In this subject, he prepared a complete exposition of the absolute differential calculus in continuous function space.Footnote 12 Conforto could also devote himself to items related with physical mathematics. He dealt with the problem of impulses in elastic isotropic bodies.Footnote 13

When he came back to Italy, Conforto fulfilled military obligations, as second lieutenant of artillery, and he was attached to the 13th Artillery Regiment and stationed in Orvinio, near the city of Rieti, during the months of July and August 1932.

The 1930s of the nineteenth century marked the beginning of Conforto’s scientific growth. After a further period of study and training at the Fondazione Beltrami, since the academic year 1933–1934, Conforto began his teaching activity at the University of Rome. He initially was temporary assistant (assistente incaricato) of Guido Castelnuovo in the chair of analytical and descriptive geometry. Then, in October 1934, Conforto competed for an assistant position for the chair of analytical and projective geometry. Conforto won the competition and gained the assistant position. He was tenured assistant (assistente di ruolo) in the chair of analytical geometry from the academic year 1934–1935 to the academic year 1938–1939. Conforto’s educational activity was always very appreciated, as it is confirmed in the report of the Exam Commission: “Brilliant and very precise speaker, completely familiar with the subject, he was able to confidently guide students’ knowledge.”Footnote 14

After Castelnuovo’s retirement (1935), Conforto became Enrico Bompiani (1889–1975)’s assistant in the same chair. In Rome, Conforto was also in touch and strongly influenced by the geometers Federigo Enriques and Francesco Severi. Thanks to Enriques and Severi, Conforto approached algebra and algebraic geometry, which represented the new mathematical research fields.Footnote 15

In January 1936, Enriques proposed Conforto as volunteer assistant for the chair of higher geometry. After having attended the lessons given by Enriques, Conforto collected them in the book Le superficie razionali, which was published some years later in 1939.Footnote 16 The handbook was intended for university students of mathematics, and it can be considered a sort of “natural continuation” of the handbook Teoria geometrica delle equazioni e delle funzioni algebriche [63] by F. Enriques and O. Chisini, which is often quoted.Footnote 17Conforto took inspiration from Enriques’ lessons of higher geometry but also from the classical theorems by Luigi Cremona, Alfred Clebsch (1833–1872), and Eugenio Bertini (1846–1933), revised according to a more modern point of view.Footnote 18 As regards Conforto’s original contribution, it dealt with some researches that he had published some years before and that he used for the writing of the handbook. He referred to two works about Halphen pencils (fasci di Halphen): one note about surfaces common to two families of rational quartics with double points, discovered by Noether (superficie comuni alle due famiglie di quartiche razionali con punto doppio, scoperte da Noether), a critical addition to the reduction of rational double planes (complemento critico portato alla riduzione dei piani doppi razionali), and one note about the bisection of the canonical series over entities of fourth genre (la nota sulla bisezione della serie canonica sopra gli enti di genere quattro).Footnote 19 Inside the handbook, at the end of some chapters, the reader can find wide and useful historical notes that prove Conforto’s interest for historical aspects in the teaching of mathematics.Footnote 20 As regards the classification of the fourth-degree surfaces, he quoted international but also Italian works, starting from the second half of the nineteenth century: A. Cayley (1864), L. Cremona (1868), A. Clebsch (1868, 1870), M. Noether (1871), G. Darboux (1873), C. Segre (1884), G. Castelnuovo (1894), H. Mohrmann (1923), and G. Gherardelli (1936).

3.1 Conforto at INAC

During the 1930s, Conforto began to collaborate with INAC. The Institute, originally founded by Mauro Picone in Naples (1927), was later moved to Rome, where it began its scientific activity in October 1933.Footnote 21

The Institute is a scientific institution able to subsidize the experimental sciences and the technique, in the quantitative mathematical analysis of their problems. It carries out its research aimed at perfecting or creating mathematical analysis methods that respond to the fulfillment of the aforementioned task. Upon request, it provides study, collaboration and consultancy services for mathematical investigations in various applications, including industry.Footnote 22

At the Institute, mathematical applications were studied in order to try to solve concrete problems, i.e., problems about aerodynamics, elasticity, and building science. As a consultant of the Institute, Conforto was involved in such kind of studies, also in collaboration with other researchers. Together with Tullio Viola (1904–1985), Conforto dealt with the numerical solution of a seismology problem, which was proposed by the geodynamic observatory of Padua (1936).Footnote 23 Other topics were the vibration of aircrafts (1937)Footnote 24 and the elastic deformation of a homogeneous and isotropic dihedron (1941).Footnote 25 This last research solved a problem related to the fixing of great lenses, which was proposed by the National Optical Institute of Florence.

One of the Institute’s activities was the preparation of a handbook for the calculus of a continuous flexed beam subject to an axial thrust. The handbook, written by Conforto jointly with Lamberto Cesari (1910–1990) and Carlo Minelli (1898–1954), was prepared for aeronautical constructions.Footnote 26 All these works, despite the evident theoretical part, gave also important practical contribution and proved the close connection between technology and pure science.

3.2 The Scientific Relationship with Francesco Severi

When, in the autumn of 1936, Conforto obtained a lecturing post (libera docenza) in analytical geometry with elements of projective and descriptive geometry with drawing at the University of Rome, he was going to almost definitively orient his scientific interest toward algebraic geometry. This scientific tendency was stimulated by the presence at the University of Rome of Guido Castelnuovo, Federigo Enriques, and, most of all, Francesco Severi, to whom Conforto got closer.

In those years, Severi became the main reference point for Italian school of algebraic geometry. Conforto attended the lessons about algebraic varieties given by Severi from the a.a. 1936–1937 until 1940–1941, first at the University of Rome and later at INdAM.Footnote 27

During the 1930s of the twentieth century, Conforto’s academic career developed along different directions, not only inside the University of Rome but also at INdAM. Since 1939, Conforto was regular professor of analytical and descriptive geometry at the Faculty of Science of the University of Rome, together with Enrico Bompiani.Footnote 28

From 1939, the year of its foundation, to 1953, Conforto taught many courses at INdAM on different topics about algebraic geometry: abelian functions, geometry of algebraic surfaces, and abelian modular functions.Footnote 29 Severi positively remembered Conforto’s collaboration to the courses of INdAM.

Fabio Conforto was one of our best colleagues at INdAM. He in fact began his collaboration at the moment the Institute began its life and its activities in the year 1939–40. Conforto’s lessons represented a model of the teaching in an Institute aimed to information and scientific routing. They always contain a personal and re-elaborated version of theories and results of researches as well as recommendation of new problems for the researchers. I [Francesco Severi] remembered the international appeal that were gained by Conforto’s courses, not only those that were published by the Institute, but also those, like a course about the theory of the automorphic functions, that have never been published.Footnote 30

Conforto published a lithographed edition of his lessons about abelian functions and Riemann matrices (1942). The book Funzioni abeliane e matrici di Riemann, which reproduced Conforto’s lessons held at INdAM in 1941, is divided into two parts: in the first one, the author developed the theory of abelian functions, generalizing a theorem stated by Appell in 1891. In the second chapter, Conforto established the links with algebraic geometry.Footnote 31 Another later volume of lessons on abelian modular functions (1951) was edited by his pupil Mario Rosati. In his exposition, Conforto followed on from previous development made by Carl Ludwig Siegel (1896–1981) and provided a reconstruction of all the subjects known at the time.Footnote 32

4 Conforto and WWII

The Italian political-military events soon intersected with the personal and professional ones of Conforto. After the outbreak of WWII (1 September 1939), Conforto was very soon called to arms with the rank of Lieutenant of Artillery and assigned to the First Regiment of Artillery of Foligno (16 November 1939). On 1 December 1939, he received the news that he won the academic competition for the chair of extraordinary professor of analytical geometry with elements of projective and descriptive geometry with drawing at the University of Rome. The chair was previously held by Gaetano Scorza (1876–1939).Footnote 33

Conforto’s scientific work shows an original researcher, gifted with open-mindedness and suitable abilities to put them in place. The matters he poses himself have always a real interest and are always brilliantly carried out. […] We can also add Conforto’s deep knowledge with the most recent and highest fields of algebraic geometry, created by Severi, and the sharpness with which he knows how to pass from geometric matters to others of mathematical physics and analysis, bringing a precious set of knowledge that let him achieve the proposed purpose. Conforto’s excellent teaching skills are known.Footnote 34

Soon after the winning of the academic competition, Conforto was sent on leave on request of the University of Rome. There were two biennial courses of analytical and projective geometry at the University of Rome, whose regular teachers were Fabio Conforto and Enrico Bompiani. During the month of November 1939, Bompiani held both the chairs, because of Conforto’s military task. Since 7 December 1939, Conforto obtained an extraordinary license of 30 days in order to carry on his university course. Considering the importance of this teaching, which was aimed at about 500 students, the Rector Pietro De Francisci asked later for an unlimited license for the rest of the academic year.Footnote 35 Conforto’s teaching activity both at the University and at INdAM was very relevant and appreciated. That’s why he was often asked for military leave.

Despite military commitments, in November 1942, Conforto attended the Mathematical Congress of Rome, which took place between 8 and 12 November, when the fighting of WWII was at its most intense. The Congress was promoted by INdAM, organized and chaired by Severi, who held the opening lecture about contemporary mathematics and mathematicians (Matematica e matematici d’oggi). Although described as an international congress, only a few specially invited foreigners attended the Congress. Among the 137 participating mathematicians, there were 17 foreigners, who came from “not enemy” nations.Footnote 36

One month later (on 1 December 1942), Conforto was appointed full professor in the chair of analytical geometry (with elements of projective and descriptive geometry) at the University of Rome.Footnote 37

Military tasks slowed down Conforto’s scientific activity. During the years 1942–1943, he wrote a joint paper together with Annibale Comessatti (1886–1945).Footnote 38 Because of WWII, Conforto was unable to fully practice his university tasks because he had to alternate between military service and the studies aimed at military applications at INAC. During the first part of 1943, Conforto again worked at the University of Rome, at INdAM, and at INAC. In this period, Picone’s Institute was undertaking military applications as part of the war effort. In July 1943, Conforto went to Germany together with Picone. The journey was aimed to develop scientific relationship with German mathematicians.Footnote 39 Conforto and Picone visited some important German universities: Jena, Berlin, Hamburg, Heidelberg, Darmstadt, and Braunschweig. They were in touch with the main mathematicians of those universities.Footnote 40 Picone hoped for collaboration between INAC and the German institute of Braunschweig.Footnote 41

4.1 Difficult Years: Rome, Reggio Calabria, Lecce

Meanwhile in Italy the political situation was quickly changing. On 9 July 1943, Allied forces invaded Sicily. The Allied landing on mainland Italy took place on 3 September 1943 in Reggio Calabria and on 9 September in Salerno on the western coast. As regards the Roman situation, on 19 July 1943, Rome had been bombed by Allied planes, causing many damages also to University structures. On 25 July, Mussolini was deposed. On 8 August, Conforto decided to volunteer for military service. He was firstly assigned to the Artillery Regiment in Foligno, and then, on 16 August, he was moved to Reggio Calabria, where he joined the Italian Army. After the Allied landing in Reggio Calabria (3 September 1943), Conforto was taken prisoner. Because of war events, for 10 months, he had no contact with his family in Rome.

After the Armistice (signed on 8 September 1943), Conforto was released and sent to Lecce, where he worked for the Minister of War and at the Military Academy.Footnote 42 Conforto taught descriptive geometry and rational mechanics. During this period, he also collected and published the lectures he gave at the Military Academy.Footnote 43 On 4 June 1944, Rome fell to the Allies and Conforto could contact his family. In August, he was able to return to Rome and be reunited with his family. On 20 December 1944, the period of military leave ended. Conforto came back to his civil life, and he could resume his research and teaching activity on an ongoing basis.Footnote 44 During the years 1946 and 1947, he was also particularly active on the editorial side, publishing many textbooks for university and secondary school, often in collaboration with academic colleagues.Footnote 45

In 1948, Conforto oriented his research interest toward quasi-abelian functions, soon after the publication of the work by Severi (Funzioni quasi abeliane [75]). Conforto’s idea was to create for the quasi-abelian case a theory that was similar to that of Riemann matrices for the abelian functions. The paper Sopra le trasformazioni in sé della varietà di Jacobi … contained the first construction of an arithmetical theory of the quasi-abelian functions.Footnote 46

5 Conforto’s Scientific Journeys

The years following the end of WWII were particularly important for Conforto’s international achievement. He took part in many congresses, and he was invited to lecture both in Italy and abroad. In the summer of 1947, Conforto was sent by CNR to the International Congress on Engineering Education in Darmstadt as Italian delegate. In the section “Mathematics and Physics,” presented by Prof. Alwin Walther, Conforto gave a talk about the latest contributions gained at INAC, thanks to the researches made by Picone and his pupils, in the field of integration of partial differential equations. Conforto underlined that these new methods required powerful calculating machines for their numerical development. These kinds of machines, recently built in America, were still lacking in Italy.

1950 was probably the year of Conforto’s consecration on an international level. Between January and February, he was invited by many European universities to give a series of conferences about algebraic geometry.Footnote 47

At the end of summer 1950, Conforto took part to the International Congress of Mathematicians at Cambridge (Massachusetts, USA). Conforto travelled to the USA together with Beniamino Segre (1903–1977). After the Congress, the two mathematicians spent almost a semester as invited professors at the Institute for Advanced Studies of Princeton (October–November 1950). In a letter of introduction, prepared for Conforto in order to go to the USA, Guido Castelnuovo hoped for collaboration between Conforto and American mathematicians.Footnote 48

Dr. Fabio Conforto was for a period of many years my Assistant at the University of Rome. He is now full Professor at that University where he teaches the same Course I used to teach before my retirement from the University. He is an excellent teacher, a mathematician with a very large cultural background, an author of very good works in analytical geometry, in analysis (theory of Abel’s functions) and in applied mathematics. He has taught very well many courses in the different branches of high mathematics. He is a person which I highly recommend, and I firmly believe that if he could sojourn for some time in an American Institution of high learning, it would be of a very great advantage for establishing more strict relations between the work of the Italian and the American mathematicians, and moreover it would be of a great advantage for the progress of our Science.Footnote 49

During the years 1951 and 1952, Conforto travelled extensively in Europe. He took part to international congresses and gave lectures by invitation of some European scientific societies in Austria, Switzerland, Germany, and Belgium.Footnote 50 This was a successful period. Conforto was internationally appreciated.Footnote 51

However, back in Italy, Conforto became seriously ill in February 1953. He gave some lectures at INdAM on abelian modular functions. In autumn 1953, his health conditions were getting worse. Even when he was taken to a clinic, he still had his books with him as he struggled to work until the end. Conforto died in Rome on 24 February 1954.Footnote 52

Following Conforto’s death, some works based on his lecture notes were published by his colleagues and students. In 1956, the Austrian mathematician Wolfgang Gröbner published a revised version of Conforto’s lectures about abelian functions. The volume “Abelian functions and algebraic geometry” [49] was based on lecture notes for courses given between 1940 and 1951. The lecture notes were collected by Conforto’s pupils Mario Rosati and Aldo Andreotti.Footnote 53

Introduzione alla topologia [50] consisted of the lectures Conforto had given at the University of Rome in the 5 years before his death. The lectures were collected by Mario Benedicty, another student of Conforto.Footnote 54

6 Conclusions

In just over 20 years of scientific activity and despite the prolonged stops due to military service, WWII, and imprisonment, Fabio Conforto published a hundred works about algebraic geometry, algebra, analysis, theoretical and applied mathematics, and history of mathematics. These works were evidence of his extraordinary versatility.

Finally, we cannot fail to mention Conforto’s commitment as an editor. Since 1939, he was member of the editorial board of the journal Rendiconti del Seminario Matematico della R. Università di Roma (now Rendiconti di matematica e delle sue applicazioni).Footnote 55 Soon after the end of WWII, Conforto took part in the editorial project of the Enciclopedia Italiana. He collaborated with Mario Niccoli (1904–1964), preparing both mathematical and biographical entries. Besides it, Conforto wrote an encyclopedic article for the Enciclopedia delle Matematiche Elementari, together with Severi, and an article about the postulates of Euclidean and non-Euclidean geometry in the Repertorio di matematiche.Footnote 56

The vastness of Conforto’s scientific interests is evidenced not only by many reviews, published in national and international journals, like Bollettino dell’Unione Matematica Italiana, Zentralblatt für Mathematik und ihre Grenzgebiete, and Mathematical Reviews, but also by various historical and educational papers. As regards Conforto’s contributions about the history of mathematics, he wrote three collective articles on Italian scientific research and the development of algebraic geometry in Italy.Footnote 57 He devoted two papers to Bonaventura Cavalieri and Evangelista Torricelli, their life and scientific works.Footnote 58 The centenary of the publication of Riemann’s thesis occasioned the publication of a short note.Footnote 59

Conforto was also interested in issues related to the teaching of mathematics, as confirmed by some articles published in the journal Archimede, addressed to teachers and connaisseurs of pure and applied mathematics.Footnote 60

After having recalled Conforto’s scientific work, it’s evident that

he never left the idea of a unified vision of mathematical sciences. As far as possible he aimed at connecting the most varied theories, as witnessed by his works.Footnote 61