<p>Let <i>k</i> be a field of characteristic zero. Let <InlineEquation ID="IEq1"> <EquationSource Format="TEX">\(f\in k[x,y]\)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mi>f</mi> <mo>∈</mo> <mi>k</mi> <mo stretchy="false">[</mo> <mi>x</mi> <mo>,</mo> <mi>y</mi> <mo stretchy="false">]</mo> </mrow> </math></EquationSource> </InlineEquation> be a reduced homogeneous polynomial. In this article, for every integer <InlineEquation ID="IEq2"> <EquationSource Format="TEX">\(n\in {\textbf{N}}\)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mi>n</mi> <mo>∈</mo> <mi mathvariant="bold">N</mi> </mrow> </math></EquationSource> </InlineEquation>, we study the general component <InlineEquation ID="IEq3"> <EquationSource Format="TEX">\(\mathscr {G}_n(\mathscr {C})\)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <msub> <mi mathvariant="script">G</mi> <mi>n</mi> </msub> <mrow> <mo stretchy="false">(</mo> <mi mathvariant="script">C</mi> <mo stretchy="false">)</mo> </mrow> </mrow> </math></EquationSource> </InlineEquation> of the jet scheme <InlineEquation ID="IEq4"> <EquationSource Format="TEX">\({\mathscr {L}}_{n}(\mathscr {C})\)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <msub> <mi mathvariant="script">L</mi> <mi>n</mi> </msub> <mrow> <mo stretchy="false">(</mo> <mi mathvariant="script">C</mi> <mo stretchy="false">)</mo> </mrow> </mrow> </math></EquationSource> </InlineEquation> of level <i>n</i>, associated with the affine plane curve <InlineEquation ID="IEq5"> <EquationSource Format="TEX">\(\mathscr {C}=\mathop {\textrm{Spec}}(k[x,y]/\langle f\rangle )\)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mi mathvariant="script">C</mi> <mo>=</mo> <mtext>Spec</mtext> <mo stretchy="false">(</mo> <mi>k</mi> <mo stretchy="false">[</mo> <mi>x</mi> <mo>,</mo> <mi>y</mi> <mo stretchy="false">]</mo> <mo stretchy="false">/</mo> <mo stretchy="false">⟨</mo> <mi>f</mi> <mo stretchy="false">⟩</mo> <mo stretchy="false">)</mo> </mrow> </math></EquationSource> </InlineEquation>. The reduced <i>k</i>-scheme <InlineEquation ID="IEq6"> <EquationSource Format="TEX">\(\mathscr {G}_n(\mathscr {C})\)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <msub> <mi mathvariant="script">G</mi> <mi>n</mi> </msub> <mrow> <mo stretchy="false">(</mo> <mi mathvariant="script">C</mi> <mo stretchy="false">)</mo> </mrow> </mrow> </math></EquationSource> </InlineEquation> is defined as the Zariski closure of the (open) subset formed by the <i>n</i>-jets centered at the regular locus of <InlineEquation ID="IEq7"> <EquationSource Format="TEX">\(\mathscr {C}\)</EquationSource> <EquationSource Format="MATHML"><math> <mi mathvariant="script">C</mi> </math></EquationSource> </InlineEquation>. Our work yields both theoretical results, mainly by constructing an isomorphism between the algebra <InlineEquation ID="IEq8"> <EquationSource Format="TEX">\(G_{n+1}:={\mathcal {O}}(\mathscr {G}_{n+1}(\mathscr {C}))\)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <msub> <mi>G</mi> <mrow> <mi>n</mi> <mo>+</mo> <mn>1</mn> </mrow> </msub> <mo>:</mo> <mo>=</mo> <mi mathvariant="script">O</mi> <mrow> <mo stretchy="false">(</mo> <msub> <mi mathvariant="script">G</mi> <mrow> <mi>n</mi> <mo>+</mo> <mn>1</mn> </mrow> </msub> <mrow> <mo stretchy="false">(</mo> <mi mathvariant="script">C</mi> <mo stretchy="false">)</mo> </mrow> <mo stretchy="false">)</mo> </mrow> </mrow> </math></EquationSource> </InlineEquation> and the Rees algebra obtained from <InlineEquation ID="IEq9"> <EquationSource Format="TEX">\(G_n\)</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mi>G</mi> <mi>n</mi> </msub> </math></EquationSource> </InlineEquation> by blowing up the singular locus of <i>any</i> <InlineEquation ID="IEq10"> <EquationSource Format="TEX">\(G_n\)</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mi>G</mi> <mi>n</mi> </msub> </math></EquationSource> </InlineEquation>-derivation on <InlineEquation ID="IEq11"> <EquationSource Format="TEX">\(G_{n+1}\)</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mi>G</mi> <mrow> <mi>n</mi> <mo>+</mo> <mn>1</mn> </mrow> </msub> </math></EquationSource> </InlineEquation>, and constructive results, by proposing Gröbner bases associated with a presentation of <InlineEquation ID="IEq12"> <EquationSource Format="TEX">\(G_{n+1}\)</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mi>G</mi> <mrow> <mi>n</mi> <mo>+</mo> <mn>1</mn> </mrow> </msub> </math></EquationSource> </InlineEquation>. As an application, we show how to connect a presentation of <InlineEquation ID="IEq13"> <EquationSource Format="TEX">\(G_1\)</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mi>G</mi> <mn>1</mn> </msub> </math></EquationSource> </InlineEquation> to the equation of the dual curve of any projective plane curve with a specific condition at the line at infinity.</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

General jet components of homogeneous plane curve singularities

  • Mario Morán Cañón,
  • Julien Sebag

摘要

Let k be a field of characteristic zero. Let \(f\in k[x,y]\) f k [ x , y ] be a reduced homogeneous polynomial. In this article, for every integer \(n\in {\textbf{N}}\) n N , we study the general component \(\mathscr {G}_n(\mathscr {C})\) G n ( C ) of the jet scheme \({\mathscr {L}}_{n}(\mathscr {C})\) L n ( C ) of level n, associated with the affine plane curve \(\mathscr {C}=\mathop {\textrm{Spec}}(k[x,y]/\langle f\rangle )\) C = Spec ( k [ x , y ] / f ) . The reduced k-scheme \(\mathscr {G}_n(\mathscr {C})\) G n ( C ) is defined as the Zariski closure of the (open) subset formed by the n-jets centered at the regular locus of \(\mathscr {C}\) C . Our work yields both theoretical results, mainly by constructing an isomorphism between the algebra \(G_{n+1}:={\mathcal {O}}(\mathscr {G}_{n+1}(\mathscr {C}))\) G n + 1 : = O ( G n + 1 ( C ) ) and the Rees algebra obtained from \(G_n\) G n by blowing up the singular locus of any \(G_n\) G n -derivation on \(G_{n+1}\) G n + 1 , and constructive results, by proposing Gröbner bases associated with a presentation of \(G_{n+1}\) G n + 1 . As an application, we show how to connect a presentation of \(G_1\) G 1 to the equation of the dual curve of any projective plane curve with a specific condition at the line at infinity.