Jorge Manuel Sotomayor Tello (25 March 1942 – 7 January 2022) was a Peruvian-born Brazilian mathematician who worked on differential equations,[2]bifurcation theory, and differential equations of classical geometry.
He is one of five sons of Alfonso Sotomayor Ibarra, an accountant, and Clara Rosa Tello de Sotomayor. He was married to Marilda Antonia de Oliveira Sotomayor and had two children.
Sotomayor earned his Ph.D. from the IMPA in 1964 under the supervision of Maurício Peixoto at the age of 22.
In the dissertation Estabilidade Estrutural de Primeira Ordem e Variedades de Banach ("First order structural stability and Banach manifolds") he presented a geometric reinterpretation and extension of the fruitful notions and results relating bifurcations and stability that were introduced by A. A. Andronov and E. A. Leontovich.[2][3][4]
Sotomayor visited the University of California at Berkeley during 1966–1968.
Sotomayor is the author of the textbooks Lições de Equações Diferenciais Ordinárias, IMPA, Projeto Euclides, (1979), Singularidades de Aplicações Diferenciáveis, ELAM (1976) and Curvas Definidas por Equações Diferenciais no Plano, 13o Colóquio Brasileiro de Matemática, IMPA, (1981). He also translated essays of Henri Poincaré into Portuguese, which were published in a book under the title Um Poeta, um Matemático e um Físico: Três Ensaios Biográficos por Henri Poincaré, EDUSP,(2008).
He is also author of the books Lines of Curvature and Umbilical Points on Surfaces, 18o CBM, Publicações Matemáticas, IMPA,(1991) with Carlos Gutierrez, reprinted and updated as Structurally
Configurations of Lines of Curvature and Umbilic Points on Surfaces,
Lima, Monografias del IMCA, (1998) and Differential Equations of Classical Differential Geometry, a Qualitative Theory, 27o CBM, Publicações Matemáticas, IMPA, (2009) with Ronaldo Garcia.
Introduced, with Carlos Gutierrez, the concept of "principal configuration" of curvature lines on surfaces. See Structurally Stable Configurations of Lines of Principal Curvature", Astérisque, França, v. 98–99, p. 195–215, (1982). The ideas leading to his work in this subject—traced back to the classical work of G. Monge, C. Dupin and G. Darboux—are discussed in his essay Monge's Ellipsoid. This research has been elaborared and extended in several directions by Sotomayor and his collaborators to include a large class of the differential equations of classical geometry (for example, the asymptotic lines, the axial curvature lines, the lines of mean curvature) and other classes of manifolds (for example, algebraic surfaces in 3 and 4 four dimensional Euclidean spaces).
Death
He died on 7 January 2022, at the age of 79.
[6][7][8][9]
Selected publications
Sotomayor, J. (1993). "O elipsóide de Monge"(PDF). Revista Matemática Universitária. 15: 33–47.
Sotomayor, J.; Garcia, R. (2016). "Historical Comments on Monge's Ellipsoid and the Confgurations of Lines of Curvature on Surfaces". Antiquitates Mathematicae. 10: 348–354.
"with C. Gutiérrez: Structurally Stable Configurations of Lines of Principal Curvature", Astérisque, França, v. 98--99, p. 195--215, (1982).
Sotomayor, J. (2021). "An encounter of classical differential geometry with dynamical systems in the realm of structural stability of principal curvature configurations". São Paulo Journal of Mathematical Sciences. 16: 256–279. doi:10.1007/s40863-021-00231-6. S2CID236365729.