TY - JOUR AU - Diego Cordoba TI - Nonexistence of simple hyperbolic blow-up for the quasi-geostrophic equation JO - Annals of mathematics PY - 1998 VL - 148 IS - 3 UR - http://geodesic.mathdoc.fr/articles/10.2307/121037/ DO - 10.2307/121037 ID - 10_2307_121037 ER -