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arXiv · 1009.6109

Unitals in $PG(2,q^2)$ with a large 2-point stabiliser

L. Giuzzi·G. Korchmáros
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Abstract

Let $\cU$ be a unital embedded in the Desarguesian projective plane $\PG(2,q^2)$. Write $M$ for the subgroup of $\PGL(3,q^2)$ which preserves $\cU$. We show that $\cU$ is classical if and only if $\cU$ has two distinct points $P,Q$ for which the stabiliser $G=M_{P,Q}$ has order $q^2-1$.

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L. Giuzzi, G. Korchmáros. 2011-07-06. Unitals in $PG(2,q^2)$ with a large 2-point stabiliser. https://doi.org/10.1016/j.disc.2011.03.017

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