Image of the Nash map in terms of wedges

M. Lejeune-Jalabert (Lecture Notes in Math., vol. 777, Springer-Verlag, 1980, pp. 303–336) proposed the following ‘problem of wedges’: let X be a surface over an algebraically closed field k of characteristic zero. Given a wedge $\text{φ}\text{:}\text{Spec}\text{k[[ξ,t]]→X}$, whose special arc lifts to the minimal resolution Y of X in an arc transversal to an irreducible component of the exceptional locus in a general point, does φ lift to Y? The main result in this Note is to extend this problem to a problem of wedges in a variety X of any dimension and to prove that, if the wedge problem is true for X, then the Nash problem is true for X. From this, necessary and sufficient conditions are given for an essential divisor to belong to the image of the Nash map, and we conclude that the Nash problem is true for sandwiched surface singularities. To cite this article: A.J. Reguera, C. R. Acad. Sci. Paris, Ser. I 338 (2004).