2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/73537Let X be a smooth projective curve over a field of characteristic p>0 and G a finite group of automorphism of X. Let n(X,G) be the characteristic of the versal equivariant deformation ring R(X,G) of (X,G). When the ramification is weak (i.e. all second ramification groups are trivial),we prove that n(X,G) is 0 or p and we compute R(X,G).in french. Second version: new, more complete proofs (not assuming a priori that lifts are fractional linear transformations), 20 pagesAlgebraic GeometryNumber Theory14H37text