Blow Ups of Complex Solutions of the 3D-Navier-Stokes System
  We consider complex-valued solutions of the three-dimensional Navier-Stokes system without external forcing on $R^3$. We show that there exists an open set in the space of 10-parameter families of initial conditions such that for each family from this set there are values of parameters for which the solution develops blow up in finite time. 
Dong Li, Yakov Sinai