[Retros] About T.Orban problem; Yefim's letter 01/12/2005

[Nicolas.Dupont at math.univ-lille1.fr]

>> Question : is it possible to go one step further ? that is several

>> solutions in N and N+1 moves, but only one solution in N+2 moves ?

>

> No.  Start by popping a knight out and back; that turns any solution

> in N moves into 16 solutions in N+2 moves.

>

> Seth


Of course, I thought about that possibility. And it doesn't prove that the
answer to my question is obviously No. For example,  let's consider a pg
where it is impossible to start by popping a knight.