Maximal \((n,3)\)-arcs in PG(2,11)
In a projective plane an \((n,r)\)-arc is a set of \(n\) points, no \((n+1)\) of which are collinear. This generalizes the idea of an \(n\)-arc -- a set of \(n\) points, no three of which are collinear. An \((n,r)\)-arc is complete if it is not included in an \((n+1,r)\)-arc. By a computer based search exploiting the fact that an \((n,3)\)-arc with \(n\geq 21\) contains an arc of size 7, the authors show that the largest size of an \((n,3)\)-arc in \(PG(2,11)\) is 21.
scientific article; zbMATH DE number 1369796