ABSTRACT
Suppose that a projective plane of order n contains a {w;A} arc. Then it also contains a complementary {n2 + n + 1 − w;n + 1 − A} arc, where n + 1 − A = {n+ 1− a : a ∈ A}.
2.28 Example Let pi be PG(2, n) where n = 2k. Then pi contains a set A of n+ 2 points, no two collinear (an oval or hyperoval). A is a {0, 2}-arc of order n+ 2 in pi.
