Ferrera Cuesta, JuanPuente Muñoz, María Jesús De La2023-06-202023-06-2019940092-787210.1080/00927879408825172https://hdl.handle.net/20.500.14352/57278Let f : R(2) --> R be an open polynomial function. Then, f changes sign across V(f) (alternatively around a singular point of V(f)) and the function c : R --> N expressing the number c(lambda) of connected components of the lambda-level curve of f is lower semicontinuous; it has removable singularity at every value lambda which is critical and is not a real critical value at infinity for f.journal articlehttp://www.tandfonline.com/doi/pdf/10.1080/00927879408825172http://www.tandfonline.com/metadata only access517.986.6517.518.45Open polynomial functionReal planeReal lineSignLevel curvesMatemáticas (Matemáticas)12 Matemáticas