A unital in the classical projective plane PG_2(q^2) is a set of q^3 + 1 points such that every line meeting two of these points meets exactly q + 1 of them.

IsUnital(U) : { PlanePt } -> BoolElt

Given a set of points U belonging to a projective plane defined over a field of cardinality q^2, return true if U is a unital.

Given a unital U in the projective plane P, return the set of tangents to the points of U.

The set of intersections of the unital U with the tangents to U which pass through the point p.