title: Hyperbolic Methods for Einstein's Equations.
abstract: I review evolutionary aspects of general relativity, in particular those related to the hyperbolic character of the field equations and to the applications or consequences that this property entails. I look at several approaches to obtaining symmetric hyperbolic systems of equations out of Einstein' equations by either removing some gauge freedoms from them, or by considering certain linear combinations of a subset of them.
authors.affiliation: Universidad Nacional de Córdoba, FaMAF, Ciudad Universitaria, Córdoba, 5000 Argentina.
authors.forename: Oscar A
authors.initials: OA
authors.lastname: Reula