Codewords for Projective Planes from Sets of Type (s, t)

Let Π^* be a projective plane of order n² having a Baer subplane Π, and let C be the code of Π^* over a prime field F_p, where p divides n. If Π contains a set K of type (s, t), then it is shown that the incidence vectors of certain sets of points defined through K are, subject to some congruence relations, in C^⊥, and sometimes in C ∩ C^⊥. Copyright 1994, 1999 Academic Press