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Algebraic cones - MaRDI portal

Algebraic cones (Q845232)

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Algebraic cones
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    Algebraic cones (English)
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    5 February 2010
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    Answering a question of Adjamagbo asked in a letter dated July 9, 2009, the author proofs the following Theorem. Let \(X\) be an irreducible algebraic variety. Then the conditions (i) \(X\) is a cone; (ii) there exists an action of \(M_m\) on \(X\) with a unique fixed point; (iii) there exists an action of \(G_m\) on \(X\) having a fixed point which is a unique closed orbit are related by the implications (i) \(\Rightarrow\) (ii) \(\Rightarrow\) (iii); moreover, if \(X\) is normal, then (iii) \(\Rightarrow\) (i).
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    algebraic cone
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    monoid action
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    group action
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    orbit
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    action with unique fixed point
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    algebra automorphism
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    stable ideal
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    irreducible algebraic variety
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