Re: The actual quote from the Post AAS article

[willett@cbnewsl.cb.att.com (david.c.willett)]

From article <SRCTRAN.93Mar17170253@world.std.com>, by srctran@world.std.com (Gregory Aharonian):
> 
>>It seems to me that the complexity of an ATC system would increase similarly
>>to the N-body problem from physics.  An example of such a problem is to
>>predict the motion of an electron travelling through a distribution of 
>>charges.  If memory serves, that problem is O(X**n) where N is the number
>>of charges and X is the number of electrons.
> 
>    N-body problems in physics, under many conditions, can be numerically
> handle without the combinatoric explosion of calculations due to 
> interparticle forces (for example, gravitational problems can be simplified
> for cluster like problems using trees where the nodes are center-of-masses,
> while electrical problems like in quantum mechanics can be simpligfied
> using generalized potentials).
>    Unfortuantely, none of these procedures works with planes, so that there
> is little analogy to be made.
> 
> Greg Aharonian
> Source Translation & Optimization
> -- 
> **************************************************************************
> Greg Aharonian
> Source Translation & Optimiztion
> P.O. Box 404, Belmont, MA 02178

The simplifications you describe depend on the relative positions and densities
of the masses involved.  I think the analogy is apt.

-- 
Dave Willett          AT&T Federal Systems Advanced Technologies
A Theoretical Physicist is one whose existence is postulated to make
the numbers balance, but is never observed in the laboratory.