A semioval in a projective plane
is a collection of points
with the
property that for every point
of
, there exists
exactly one line of
meeting
precisely
in the point
.
There are many known constructions of and theoretical results about semiovals,
especially those that contain large collinear subsets.
In a Desarguesian plane
a conic, the set of zeroes of some nondegenerate quadratic form, is an example of a semioval
of size
that also forms an arc (i.e., no three points are collinear). As conics are minimal
semiovals, it is natural to use them as building blocks for larger semiovals. Our goal
in this work is to classify completely the sets of conics whose union forms a
semioval.
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