RT info:eu-repo/semantics/article T1 Real analytic vector fields with first integral and separatrices A1 Mol, Rogério A1 Sánchez, Fernando Sanz K1 Real analytic vector eld, rst integral, formal and analytic separatrix, reduction of singularities, index of vector elds AB We prove that a germ of analytic vector field at (R3, 0) that possesses a non-constant analytic first integral has a real formal separatrix. We provide an example which shows that such a vector field does not necessarily have a real analytic separatrix. PB Springer SN 1578-7303 YR 2019 FD 2019 LK https://uvadoc.uva.es/handle/10324/68130 UL https://uvadoc.uva.es/handle/10324/68130 LA eng NO RACSAM, Revista de la Real Academia de Ciencias Exactas, Fisicas y Naturales. Serie A. Matematicas, vol. 113 (4), 2019, 4031-4049 DS UVaDOC RD 30-jun-2024