<p>Let <i>Y</i> be an irreducible plane curve germ with branch <InlineEquation ID="IEq1"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="233_2025_10516_Article_IEq1.gif" Format="GIF" Height="17" Rendition="HTML" Resolution="72" Type="Linedraw" Width="13" /> </InlineMediaObject> <EquationSource Format="TEX">\(\zeta \)</EquationSource> <EquationSource Format="MATHML"><math> <mi>ζ</mi> </math></EquationSource> </InlineEquation> and <i>s</i> characteristic exponents. We introduce a class of truncation sequences of <InlineEquation ID="IEq2"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="233_2025_10516_Article_IEq1.gif" Format="GIF" Height="17" Rendition="HTML" Resolution="72" Type="Linedraw" Width="13" /> </InlineMediaObject> <EquationSource Format="TEX">\(\zeta \)</EquationSource> <EquationSource Format="MATHML"><math> <mi>ζ</mi> </math></EquationSource> </InlineEquation> having finite support. For a given <InlineEquation ID="IEq3"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="233_2025_10516_Article_IEq3.gif" Format="GIF" Height="24" Rendition="HTML" Resolution="72" Type="Linedraw" Width="68" /> </InlineMediaObject> <EquationSource Format="TEX">\(({\widetilde{\zeta }}_i)_{i=1,\ldots ,s}\)</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mrow> <mo stretchy="false">(</mo> <msub> <mover accent="true"> <mi>ζ</mi> <mo stretchy="true">~</mo> </mover> <mi>i</mi> </msub> <mo stretchy="false">)</mo> </mrow> <mrow> <mi>i</mi> <mo>=</mo> <mn>1</mn> <mo>,</mo> <mo>…</mo> <mo>,</mo> <mi>s</mi> </mrow> </msub> </math></EquationSource> </InlineEquation> from this class, we explicitly compute the convex hull of the minimal polynomial <InlineEquation ID="IEq4"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="233_2025_10516_Article_IEq4.gif" Format="GIF" Height="17" Rendition="HTML" Resolution="72" Type="Linedraw" Width="17" /> </InlineMediaObject> <EquationSource Format="TEX">\(f_i\)</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mi>f</mi> <mi>i</mi> </msub> </math></EquationSource> </InlineEquation> for each germ of plane curve <InlineEquation ID="IEq5"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="233_2025_10516_Article_IEq5.gif" Format="GIF" Height="16" Rendition="HTML" Resolution="72" Type="Linedraw" Width="17" /> </InlineMediaObject> <EquationSource Format="TEX">\(Y_i\)</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mi>Y</mi> <mi>i</mi> </msub> </math></EquationSource> </InlineEquation>, with branch <InlineEquation ID="IEq6"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="233_2025_10516_Article_IEq6.gif" Format="GIF" Height="22" Rendition="HTML" Resolution="72" Type="Linedraw" Width="16" /> </InlineMediaObject> <EquationSource Format="TEX">\({\widetilde{\zeta }}_i\)</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mover accent="true"> <mi>ζ</mi> <mo stretchy="true">~</mo> </mover> <mi>i</mi> </msub> </math></EquationSource> </InlineEquation>. We investigate the relationships between the semigroup of the <InlineEquation ID="IEq7"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="233_2025_10516_Article_IEq5.gif" Format="GIF" Height="16" Rendition="HTML" Resolution="72" Type="Linedraw" Width="17" /> </InlineMediaObject> <EquationSource Format="TEX">\(Y_i\)</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mi>Y</mi> <mi>i</mi> </msub> </math></EquationSource> </InlineEquation>’s, as well as the induced canonical valuations. Additionally, we provide methods for selecting truncation sequences that yield topologically equivalent approximations <InlineEquation ID="IEq8"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="233_2025_10516_Article_IEq8.gif" Format="GIF" Height="16" Rendition="HTML" Resolution="72" Type="Linedraw" Width="18" /> </InlineMediaObject> <EquationSource Format="TEX">\(Y_s\)</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mi>Y</mi> <mi>s</mi> </msub> </math></EquationSource> </InlineEquation> of <i>Y</i>. The sequence <InlineEquation ID="IEq9"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="233_2025_10516_Article_IEq3.gif" Format="GIF" Height="24" Rendition="HTML" Resolution="72" Type="Linedraw" Width="68" /> </InlineMediaObject> <EquationSource Format="TEX">\(({\widetilde{\zeta }}_i)_{i=1,\ldots ,s}\)</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mrow> <mo stretchy="false">(</mo> <msub> <mover accent="true"> <mi>ζ</mi> <mo stretchy="true">~</mo> </mover> <mi>i</mi> </msub> <mo stretchy="false">)</mo> </mrow> <mrow> <mi>i</mi> <mo>=</mo> <mn>1</mn> <mo>,</mo> <mo>…</mo> <mo>,</mo> <mi>s</mi> </mrow> </msub> </math></EquationSource> </InlineEquation> of <InlineEquation ID="IEq10"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="233_2025_10516_Article_IEq1.gif" Format="GIF" Height="17" Rendition="HTML" Resolution="72" Type="Linedraw" Width="13" /> </InlineMediaObject> <EquationSource Format="TEX">\(\zeta \)</EquationSource> <EquationSource Format="MATHML"><math> <mi>ζ</mi> </math></EquationSource> </InlineEquation> provides a unique decomposition of each polynomial <InlineEquation ID="IEq11"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="233_2025_10516_Article_IEq4.gif" Format="GIF" Height="17" Rendition="HTML" Resolution="72" Type="Linedraw" Width="17" /> </InlineMediaObject> <EquationSource Format="TEX">\(f_i\)</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mi>f</mi> <mi>i</mi> </msub> </math></EquationSource> </InlineEquation>. Given that the minimal polynomial <InlineEquation ID="IEq12"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="233_2025_10516_Article_IEq4.gif" Format="GIF" Height="17" Rendition="HTML" Resolution="72" Type="Linedraw" Width="17" /> </InlineMediaObject> <EquationSource Format="TEX">\(f_i\)</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mi>f</mi> <mi>i</mi> </msub> </math></EquationSource> </InlineEquation> can be written as a power of <InlineEquation ID="IEq13"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="233_2025_10516_Article_IEq13.gif" Format="GIF" Height="17" Rendition="HTML" Resolution="72" Type="Linedraw" Width="30" /> </InlineMediaObject> <EquationSource Format="TEX">\(f_{i-1}\)</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mi>f</mi> <mrow> <mi>i</mi> <mo>-</mo> <mn>1</mn> </mrow> </msub> </math></EquationSource> </InlineEquation> plus a tail <InlineEquation ID="IEq14"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="233_2025_10516_Article_IEq14.gif" Format="GIF" Height="16" Rendition="HTML" Resolution="72" Type="Linedraw" Width="15" /> </InlineMediaObject> <EquationSource Format="TEX">\(\delta _i\)</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mi>δ</mi> <mi>i</mi> </msub> </math></EquationSource> </InlineEquation>, our first decomposition theorem studies properties of the tail. The second decomposition theorem characterizes the decomposition of <InlineEquation ID="IEq15"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="233_2025_10516_Article_IEq14.gif" Format="GIF" Height="16" Rendition="HTML" Resolution="72" Type="Linedraw" Width="15" /> </InlineMediaObject> <EquationSource Format="TEX">\(\delta _i\)</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mi>δ</mi> <mi>i</mi> </msub> </math></EquationSource> </InlineEquation> and enables its explicit computation. To conclude, a pseudocode algorithm is presented along with an example.</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

Minimal polynomial decomposition of plane curve branch truncation using a semigroup based algorithm

  • Joao Cabral,
  • Ana Casimiro

摘要

Let Y be an irreducible plane curve germ with branch \(\zeta \) ζ and s characteristic exponents. We introduce a class of truncation sequences of \(\zeta \) ζ having finite support. For a given \(({\widetilde{\zeta }}_i)_{i=1,\ldots ,s}\) ( ζ ~ i ) i = 1 , , s from this class, we explicitly compute the convex hull of the minimal polynomial \(f_i\) f i for each germ of plane curve \(Y_i\) Y i , with branch \({\widetilde{\zeta }}_i\) ζ ~ i . We investigate the relationships between the semigroup of the \(Y_i\) Y i ’s, as well as the induced canonical valuations. Additionally, we provide methods for selecting truncation sequences that yield topologically equivalent approximations \(Y_s\) Y s of Y. The sequence \(({\widetilde{\zeta }}_i)_{i=1,\ldots ,s}\) ( ζ ~ i ) i = 1 , , s of \(\zeta \) ζ provides a unique decomposition of each polynomial \(f_i\) f i . Given that the minimal polynomial \(f_i\) f i can be written as a power of \(f_{i-1}\) f i - 1 plus a tail \(\delta _i\) δ i , our first decomposition theorem studies properties of the tail. The second decomposition theorem characterizes the decomposition of \(\delta _i\) δ i and enables its explicit computation. To conclude, a pseudocode algorithm is presented along with an example.