3 Oct 2003; Mat-Nat Faculty (UITO), room U7, 10:15-12:00

Martin Rypdal "Removeability of Singularities in the Zhang Model of SOC".

We discuss if the singularities in the Zhang model (refer to previous talks ¹,²,³) are removeable. If they are, we can construct a conjugancy to a symbolic dynamical system. We then have a natural invariant measure, and we can show that correlations decay exponentially. Moreover we can show that the topological entropy is log(N), where N is the dimension of the configuration space. On the other hand, if the topological entropy exists and is log(N), we can show that  singularities are removable in a week sense.