# On minimal blocking sets of the generalized quadrangle $Q(4, q)$

Abstract : The generalized quadrangle $Q(4,q)$ arising from the parabolic quadric in $PG(4,q)$ always has an ovoid. It is not known whether a minimal blocking set of size smaller than $q^2 + q$ (which is not an ovoid) exists in $Q(4,q)$, $q$ odd. We present results on smallest blocking sets in $Q(4,q)$, $q$ odd, obtained by a computer search. For $q = 5,7,9,11$ we found minimal blocking sets of size $q^2 + q - 2$ and we discuss their structure. By an exhaustive search we excluded the existence of a minimal blocking set of size $q^2 + 3$ in $Q(4,7)$.
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https://hal.inria.fr/hal-01184455
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• HAL Id : hal-01184455, version 1

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Miroslava Cimráková, Veerle Fack. On minimal blocking sets of the generalized quadrangle $Q(4, q)$. 2005 European Conference on Combinatorics, Graph Theory and Applications (EuroComb '05), 2005, Berlin, Germany. pp.299-302. ⟨hal-01184455⟩

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