<p>Let <i>Y</i> be a smooth cubic fourfold not containing any plane, <i>F</i> be its Fano variety of lines and <i>Z</i> be its associated LLSvS variety, parametrizing families of twisted cubics and some of their degenerations. In this short note, we show that for the general cubic fourfold the divisor of singular cubic surfaces on <i>Z</i> has two irreducible components, one of which coincides with the uniruled branch divisor of a resolution of the Voisin map <InlineEquation ID="IEq1"> <EquationSource Format="TEX">\(F\times F \dashrightarrow Z\)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mi>F</mi> <mo>×</mo> <mi>F</mi> <mo>⤏</mo> <mi>Z</mi> </mrow> </math></EquationSource> </InlineEquation>.</p>

错误:搜索内容不能为空,请输入英文关键词
错误:关键词超出字数限制,请精简
高级检索

On the uniruled Voisin divisor on the LLSvS variety

  • Franco Giovenzana

摘要

Let Y be a smooth cubic fourfold not containing any plane, F be its Fano variety of lines and Z be its associated LLSvS variety, parametrizing families of twisted cubics and some of their degenerations. In this short note, we show that for the general cubic fourfold the divisor of singular cubic surfaces on Z has two irreducible components, one of which coincides with the uniruled branch divisor of a resolution of the Voisin map \(F\times F \dashrightarrow Z\) F × F Z .