We study the Fubini property of ideals on omega and prove that
the Solecki’s ideal S is critical for this property in the Katětov order.
We show that a well-known F_sigma-ideal is critical for Hausdorff ultrafilters
in the Katětov order and, by investigating the position of this ideal in
the Katětov order, we show some of the known properties of this class
of ultrafilters, including the Fubini property.
