Sur un théorème de M. Chasles concernant les coniques homofocales
The Euler number of the normalization of an algebraic threefold with ordinary singularities
By a classical formula due to Enriques, the Euler number χ(X) of the non-singular normalization X of an algebraic surface S with ordinary singularities in P³(ℂ) is given by χ(X) = n(n²-4n+6) - (3n-8)m + 3t - 2γ, where n is the degree of S, m the degree of the double curve (singular locus) of S, t is the cardinal number of the triple points of S, and γ the cardinal number of the cuspidal points of S. In this article we shall give a similar formula for an algebraic threefold with ordinary singularities...
The multiple conical surfaces.
Tissus du plan et polynômes de Darboux
Dans cet article, nous étudions le problème de l’existence de polynômes de Darboux dans pour la dérivation .
Классификация конфигураций ранга восемь
Рациональные поверхности с пучком рациональных кривых