Pic is a contracted functor.
Polynomial algebra of constants of the Lotka-Volterra system
Let k be a field of characteristic zero. We describe the kernel of any quadratic homogeneous derivation d:k[x,y,z] → k[x,y,z] of the form , called the Lotka-Volterra derivation, where A,B,C ∈ k.
Potenzreihenerweiterung und formale Fasern in lokalen Ringen mit Approximationseigenschaft.
Preservation of the properties of the polynomial ring of the power series ring in the class of finite conductor rings.
Propriété d'approximation pour les éléments algébriques
Puiseux series solutions of ordinary polynomial differential equations: complexity study.