  We extend the notion of randomness (in the version introduced by Schnorr) to
computable Probability Spaces and compare it to a dynamical notion of
randomness: typicality. Roughly, a point is typical for some dynamic, if it
follows the statistical behavior of the system (Birkhoff's pointwise ergodic
theorem). We prove that a point is Schnorr random if and only if it is typical
for every mixing computable dynamics. To prove the result we develop some tools
for the theory of computable probability spaces (for example, morphisms) that
are expected to have other applications.
