Semi-linear representations of PGL

dc.creatorRovinsky, M.
dc.date2003-06-23
dc.date2005-03-10
dc.date.accessioned2026-07-07T13:00:55Z
dc.date.available2026-07-07T13:00:55Z
dc.descriptionLet $L$ be the function field of a projective space ${\mathbb P}^n_k$ over an algebraically closed field $k$ of characteristic zero, and $H$ be the group of projective transformations. An $H$-sheaf ${\mathcal V}$ on ${\mathbb P}^n_k$ is a collection of isomorphisms ${\mathcal V} \longrightarrow g^{\ast}{\mathcal V}$ for each $g\in H$ satisfying the chain rule. We construct, for any $n>1$, a fully faithful functor from the category of finite-dimensional $L$-semi-linear representations of $H$ extendable to the semi-group ${\rm End}(L/k)$ to the category of coherent $H$-sheaves on ${\mathbb P}^n_k$. The paper is motivated by a study of admissible representations of the automorphism group $G$ of an algebraically closed extension of $k$ of countable transcendence degree undertaken in \cite{rep}. The semi-group ${\rm End}(L/k)$ is considered as a subquotient of $G$, hence the condition on extendability. In the appendix it is shown that, if $\tilde{H}$ is either $H$, or a bigger subgroup in the Cremona group (generated by $H$ and a standard involution), then any semi-linear $\tilde{H}$-representation of degree one is an integral $L$-tensor power of $\det_LΩ^1_{L/k}$. It is shown also that this bigger subgroup has no non-trivial representations of finite degree if $n>1$.
dc.descriptionrevised version
dc.identifierhttps://arxiv.org/abs/math/0306333
dc.identifierhttp://arxiv.org/abs/math/0306333
dc.identifierSelecta Math., 11 (2005), no. 3--4, 491--522
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/225992
dc.subjectRepresentation Theory
dc.subjectAlgebraic Geometry
dc.titleSemi-linear representations of PGL
dc.typetext

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