Electronic Journal of Differential Equations, Conference 08 (2002), pp. 85-101 Title: Description of regional blow-up in a porous-medium equation Authors: Carmen Cort'azar (Univ. de Chile, Santiago, Chile) Manuel del Pino (Univ. de Chile, Santiago, Chile) Manuel Elgueta (Univ. de Chile, Santiago, Chile) Abstract: We describe the (finite-time) blow-up phenomenon for a non-negative solution of a porous medium equation of the form $$ u_t = \Delta u^m + u^m $$ in the entire space. Here $m>1$ and the initial condition is assumed compactly supported. Blow-up takes place exactly inside a finite number of balls with same radii and exhibiting the same self-similar profile. Published October 21, 2002. Math Subject Classifications: 35B40, 35B45, 35J40. Key Words: Multiple-bump; pattern formation; mathematical biology; singular perturbation.