From: bergervo@xs4all.nl   
      
   The Navier-Stokes equations can be simplified in two ways:   
   by putting to zero the compressibility and/or the viscosity,   
   which then leaves us with 4 cases..   
      
   Does the "millennium problem" of proving or disproving the   
   smoothness of the solution require the full case, or would   
   solving it for a simplified case already be enough? (I'm   
   asking because we don't want to do the work and then still   
   not get one million dollar, of course!)   
      
   I would expect that the doubly simplified case is too   
   trivial.. but is the solution in that case actually known   
   already? That would be the question:   
     "Are there solutions for a non-compressible, non-viscous   
      fluid that start with smooth initial conditions and then   
      develop a singularity?"   
      
   Since non-viscosity means the equations are time reversal   
   invariant, the question could also be: can you start with   
   a singular solution and have the time-evolution smooth it   
   out? (To me the answer seems likely to be yes, but as said,   
   I don't know whether it has been proven. It might be both   
   simple and difficult, like the Goldbach conjecture..)   
      
   --   
   Jos   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)