  We consider a problem occurring in a magnetostatic levitation. The problem
leads to a linear PDE in a strip. In engineering literature a particular
solution is obtained. Such a solution enables one to compute lift and drag
forces of the levitating object. It is in agreement with the experiment. We
show that such a solution is unique in a class of bounded regular functions.
Moreover, as a byproduct, we obtain nonstandard uniqueness results in two
linear PDEs in unbounded domains. One of them is an Eigenvalue problem for the
Laplacian in the strip in the nonstandard class of functions.
