A subset of the Hermitian surface
The authors define a ruled algebraic surface of \(\text{PG}(3,q^2)\) which they call a hyperbolic \({\mathcal Q}_F\)-set, and they prove that it is contained in a Hermitian surface of \(\text{PG}(3,q^2)\). They also characterize hyperbolic \({\mathcal Q}_F\)-sets as intersections of two Hermitian surfaces.
scientific article; zbMATH DE number 5076685