<p>In a hypergraph <i>H</i>(<i>V</i>,&#xa0;<i>E</i>), a subset of edges <InlineEquation ID="IEq1"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="10878_2025_1284_Article_IEq1.gif" Format="GIF" Height="16" Rendition="HTML" Resolution="72" Type="Linedraw" Width="53" /> </InlineMediaObject> <EquationSource Format="TEX">\(A\subseteq E\)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mi>A</mi> <mo>⊆</mo> <mi>E</mi> </mrow> </math></EquationSource> </InlineEquation> forms an edge dominating set if each edge <InlineEquation ID="IEq2"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="10878_2025_1284_Article_IEq2.gif" Format="GIF" Height="19" Rendition="HTML" Resolution="72" Type="Linedraw" Width="76" /> </InlineMediaObject> <EquationSource Format="TEX">\(e\in E\setminus A\)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mi>e</mi> <mo>∈</mo> <mi>E</mi> <mo lspace="0.15em" rspace="0.15em" stretchy="false">\</mo> <mi>A</mi> </mrow> </math></EquationSource> </InlineEquation> is adjacent to at least one edge in <i>A</i>. The edge dominating number <InlineEquation ID="IEq3"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="10878_2025_1284_Article_IEq3.gif" Format="GIF" Height="19" Rendition="HTML" Resolution="72" Type="Linedraw" Width="44" /> </InlineMediaObject> <EquationSource Format="TEX">\(\gamma '(H)\)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <msup> <mi>γ</mi> <mo>′</mo> </msup> <mrow> <mo stretchy="false">(</mo> <mi>H</mi> <mo stretchy="false">)</mo> </mrow> </mrow> </math></EquationSource> </InlineEquation> represents the smallest size of an edge dominating set in <i>H</i>. In this paper, we establish upper bounds on the edge dominating number for hypergraphs with minimum degree <InlineEquation ID="IEq4"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="10878_2025_1284_Article_IEq4.gif" Format="GIF" Height="14" Rendition="HTML" Resolution="72" Type="Linedraw" Width="12" /> </InlineMediaObject> <EquationSource Format="TEX">\(\delta \)</EquationSource> <EquationSource Format="MATHML"><math> <mi>δ</mi> </math></EquationSource> </InlineEquation>: (1) For <InlineEquation ID="IEq5"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="10878_2025_1284_Article_IEq5.gif" Format="GIF" Height="16" Rendition="HTML" Resolution="72" Type="Linedraw" Width="41" /> </InlineMediaObject> <EquationSource Format="TEX">\(\delta \le 4\)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mi>δ</mi> <mo>≤</mo> <mn>4</mn> </mrow> </math></EquationSource> </InlineEquation>, <InlineEquation ID="IEq6"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="10878_2025_1284_Article_IEq6.gif" Format="GIF" Height="21" Rendition="HTML" Resolution="72" Type="Linedraw" Width="79" /> </InlineMediaObject> <EquationSource Format="TEX">\(\gamma '(H)\le \frac{m}{\delta }\)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <msup> <mi>γ</mi> <mo>′</mo> </msup> <mrow> <mo stretchy="false">(</mo> <mi>H</mi> <mo stretchy="false">)</mo> </mrow> <mo>≤</mo> <mfrac> <mi>m</mi> <mi>δ</mi> </mfrac> </mrow> </math></EquationSource> </InlineEquation>; (2) For <InlineEquation ID="IEq7"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="10878_2025_1284_Article_IEq7.gif" Format="GIF" Height="16" Rendition="HTML" Resolution="72" Type="Linedraw" Width="41" /> </InlineMediaObject> <EquationSource Format="TEX">\(\delta \ge 5\)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mi>δ</mi> <mo>≥</mo> <mn>5</mn> </mrow> </math></EquationSource> </InlineEquation>, <InlineEquation ID="IEq8"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="10878_2025_1284_Article_IEq8.gif" Format="GIF" Height="21" Rendition="HTML" Resolution="72" Type="Linedraw" Width="79" /> </InlineMediaObject> <EquationSource Format="TEX">\(\gamma '(H)\le \frac{m}{\delta }\)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <msup> <mi>γ</mi> <mo>′</mo> </msup> <mrow> <mo stretchy="false">(</mo> <mi>H</mi> <mo stretchy="false">)</mo> </mrow> <mo>≤</mo> <mfrac> <mi>m</mi> <mi>δ</mi> </mfrac> </mrow> </math></EquationSource> </InlineEquation> holds for hypertrees and uniform hypergraphs; (3) For a random hypergraph model <InlineEquation ID="IEq9"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="10878_2025_1284_Article_IEq9.gif" Format="GIF" Height="19" Rendition="HTML" Resolution="72" Type="Linedraw" Width="61" /> </InlineMediaObject> <EquationSource Format="TEX">\(\mathcal H(n,m)\)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mi mathvariant="script">H</mi> <mo stretchy="false">(</mo> <mi>n</mi> <mo>,</mo> <mi>m</mi> <mo stretchy="false">)</mo> </mrow> </math></EquationSource> </InlineEquation>, for any positive number <InlineEquation ID="IEq10"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="10878_2025_1284_Article_IEq10.gif" Format="GIF" Height="13" Rendition="HTML" Resolution="72" Type="Linedraw" Width="40" /> </InlineMediaObject> <EquationSource Format="TEX">\(\varepsilon &gt;0\)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mi>ε</mi> <mo>&gt;</mo> <mn>0</mn> </mrow> </math></EquationSource> </InlineEquation>, <InlineEquation ID="IEq11"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="10878_2025_1284_Article_IEq11.gif" Format="GIF" Height="21" Rendition="HTML" Resolution="72" Type="Linedraw" Width="127" /> </InlineMediaObject> <EquationSource Format="TEX">\(\gamma ' (H)\le (1+\varepsilon )\frac{m}{\delta }\)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <msup> <mi>γ</mi> <mo>′</mo> </msup> <mrow> <mo stretchy="false">(</mo> <mi>H</mi> <mo stretchy="false">)</mo> </mrow> <mo>≤</mo> <mrow> <mo stretchy="false">(</mo> <mn>1</mn> <mo>+</mo> <mi>ε</mi> <mo stretchy="false">)</mo> </mrow> <mfrac> <mi>m</mi> <mi>δ</mi> </mfrac> </mrow> </math></EquationSource> </InlineEquation> holds with high probability when <i>m</i> is bounded by some polynomial function of <i>n</i>. Based on the proofs, some combinatorial algorithms on the edge dominating number of hypergraphs with minimum degree are designed.</p>

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A sharp upper bound for the edge dominating number of hypergraphs with minimum degree

  • Zhongzheng Tang,
  • Zhuo Diao

摘要

In a hypergraph H(VE), a subset of edges \(A\subseteq E\) A E forms an edge dominating set if each edge \(e\in E\setminus A\) e E \ A is adjacent to at least one edge in A. The edge dominating number \(\gamma '(H)\) γ ( H ) represents the smallest size of an edge dominating set in H. In this paper, we establish upper bounds on the edge dominating number for hypergraphs with minimum degree \(\delta \) δ : (1) For \(\delta \le 4\) δ 4 , \(\gamma '(H)\le \frac{m}{\delta }\) γ ( H ) m δ ; (2) For \(\delta \ge 5\) δ 5 , \(\gamma '(H)\le \frac{m}{\delta }\) γ ( H ) m δ holds for hypertrees and uniform hypergraphs; (3) For a random hypergraph model \(\mathcal H(n,m)\) H ( n , m ) , for any positive number \(\varepsilon >0\) ε > 0 , \(\gamma ' (H)\le (1+\varepsilon )\frac{m}{\delta }\) γ ( H ) ( 1 + ε ) m δ holds with high probability when m is bounded by some polynomial function of n. Based on the proofs, some combinatorial algorithms on the edge dominating number of hypergraphs with minimum degree are designed.