10/10/2009, 07:11 AM

(10/10/2009, 01:05 AM)mike3 Wrote: I guess the next step would be the formal proof of the existence and uniqueness of the solution.

exactly

On the other hand there is often a situation where you work with a certain law without having a proof that it is always true (e.g. map publisher relied long before having a proven basis that a map needs at most 4 colors).

Or in other words I think such proofs are really difficult to find.