J. Aust. Math. Soc.  74 (2003), 145-153
Daisy structure in Desarguesian projective planes

M. Gabriela Araujo Pardo
  Instituto de Matemáticas, UNAM
  Circuito Exterior
  Ciudad Universitaria
  México 04510 D.F.

We distribute the points and lines of $PG(2,2^{n+1})$ according to a special structure that we call the daisy structure. This distribution is intimately related to a special block design which turns out to be isomorphic to $PG(n,2)$. We show a blocking set of $3q$ points in $PG(2,2^{n+1})$ that intersects each line in at least two points and we apply this to find a lower bound for the heterochromatic number of the projective plane.
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