<p>What is the maximum length <InlineEquation ID="IEq1"> <EquationSource Format="TEX">\(\textrm{f}_\textrm{max}(\ell , \Sigma )\)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <msub> <mtext>f</mtext> <mtext>max</mtext> </msub> <mrow> <mo stretchy="false">(</mo> <mi>ℓ</mi> <mo>,</mo> <mi mathvariant="normal">Σ</mi> <mo stretchy="false">)</mo> </mrow> </mrow> </math></EquationSource> </InlineEquation> of a facial cycle of an inclusion-maximal graph with girth at least <InlineEquation ID="IEq2"> <EquationSource Format="TEX">\(\ell \)</EquationSource> <EquationSource Format="MATHML"><math> <mi>ℓ</mi> </math></EquationSource> </InlineEquation> embedded on a given surface <InlineEquation ID="IEq3"> <EquationSource Format="TEX">\(\Sigma \)</EquationSource> <EquationSource Format="MATHML"><math> <mi mathvariant="normal">Σ</mi> </math></EquationSource> </InlineEquation>? If <InlineEquation ID="IEq4"> <EquationSource Format="TEX">\(\Sigma =\mathcal {P}\)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mi mathvariant="normal">Σ</mi> <mo>=</mo> <mi mathvariant="script">P</mi> </mrow> </math></EquationSource> </InlineEquation> is a plane, we show that <InlineEquation ID="IEq5"> <EquationSource Format="TEX">\(3\ell -11\le \textrm{f}_\textrm{max}(\ell , \mathcal {P})\le 8\ell -13\)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mn>3</mn> <mi>ℓ</mi> <mo>-</mo> <mn>11</mn> <mo>≤</mo> <msub> <mtext>f</mtext> <mtext>max</mtext> </msub> <mrow> <mo stretchy="false">(</mo> <mi>ℓ</mi> <mo>,</mo> <mi mathvariant="script">P</mi> <mo stretchy="false">)</mo> </mrow> <mo>≤</mo> <mn>8</mn> <mi>ℓ</mi> <mo>-</mo> <mn>13</mn> </mrow> </math></EquationSource> </InlineEquation>. We also prove that <InlineEquation ID="IEq6"> <EquationSource Format="TEX">\(\textrm{f}_\textrm{max}(\ell , \Sigma )\)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <msub> <mtext>f</mtext> <mtext>max</mtext> </msub> <mrow> <mo stretchy="false">(</mo> <mi>ℓ</mi> <mo>,</mo> <mi mathvariant="normal">Σ</mi> <mo stretchy="false">)</mo> </mrow> </mrow> </math></EquationSource> </InlineEquation> is bounded for any integer <InlineEquation ID="IEq7"> <EquationSource Format="TEX">\(\ell \)</EquationSource> <EquationSource Format="MATHML"><math> <mi>ℓ</mi> </math></EquationSource> </InlineEquation> and any closed surface <InlineEquation ID="IEq8"> <EquationSource Format="TEX">\(\Sigma \)</EquationSource> <EquationSource Format="MATHML"><math> <mi mathvariant="normal">Σ</mi> </math></EquationSource> </InlineEquation>. For a fixed <InlineEquation ID="IEq9"> <EquationSource Format="TEX">\(\Sigma \)</EquationSource> <EquationSource Format="MATHML"><math> <mi mathvariant="normal">Σ</mi> </math></EquationSource> </InlineEquation>, we show that <InlineEquation ID="IEq10"> <EquationSource Format="TEX">\(\Omega (\ell ) =\textrm{f}_\textrm{max}(\ell , \Sigma ) = O(\ell ^2)\)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mi mathvariant="normal">Ω</mi> <mrow> <mo stretchy="false">(</mo> <mi>ℓ</mi> <mo stretchy="false">)</mo> </mrow> <mo>=</mo> <msub> <mtext>f</mtext> <mtext>max</mtext> </msub> <mrow> <mo stretchy="false">(</mo> <mi>ℓ</mi> <mo>,</mo> <mi mathvariant="normal">Σ</mi> <mo stretchy="false">)</mo> </mrow> <mo>=</mo> <mi>O</mi> <mrow> <mo stretchy="false">(</mo> <msup> <mi>ℓ</mi> <mn>2</mn> </msup> <mo stretchy="false">)</mo> </mrow> </mrow> </math></EquationSource> </InlineEquation>, while for a fixed <InlineEquation ID="IEq11"> <EquationSource Format="TEX">\(\ell \ge 6\)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mi>ℓ</mi> <mo>≥</mo> <mn>6</mn> </mrow> </math></EquationSource> </InlineEquation>, <InlineEquation ID="IEq12"> <EquationSource Format="TEX">\(\textrm{f}_\textrm{max}(\ell , \Sigma )=\Theta (g)\)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <msub> <mtext>f</mtext> <mtext>max</mtext> </msub> <mrow> <mo stretchy="false">(</mo> <mi>ℓ</mi> <mo>,</mo> <mi mathvariant="normal">Σ</mi> <mo stretchy="false">)</mo> </mrow> <mo>=</mo> <mi mathvariant="normal">Θ</mi> <mrow> <mo stretchy="false">(</mo> <mi>g</mi> <mo stretchy="false">)</mo> </mrow> </mrow> </math></EquationSource> </InlineEquation>, where <i>g</i> is the genus of <InlineEquation ID="IEq13"> <EquationSource Format="TEX">\(\Sigma \)</EquationSource> <EquationSource Format="MATHML"><math> <mi mathvariant="normal">Σ</mi> </math></EquationSource> </InlineEquation>.</p>

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Faces in Girth-Saturated Graphs on Surfaces

  • Maria Axenovich,
  • Leon Kießle,
  • Arsenii Sagdeev,
  • Maksim Zhukovskii

摘要

What is the maximum length \(\textrm{f}_\textrm{max}(\ell , \Sigma )\) f max ( , Σ ) of a facial cycle of an inclusion-maximal graph with girth at least \(\ell \) embedded on a given surface \(\Sigma \) Σ ? If \(\Sigma =\mathcal {P}\) Σ = P is a plane, we show that \(3\ell -11\le \textrm{f}_\textrm{max}(\ell , \mathcal {P})\le 8\ell -13\) 3 - 11 f max ( , P ) 8 - 13 . We also prove that \(\textrm{f}_\textrm{max}(\ell , \Sigma )\) f max ( , Σ ) is bounded for any integer \(\ell \) and any closed surface \(\Sigma \) Σ . For a fixed \(\Sigma \) Σ , we show that \(\Omega (\ell ) =\textrm{f}_\textrm{max}(\ell , \Sigma ) = O(\ell ^2)\) Ω ( ) = f max ( , Σ ) = O ( 2 ) , while for a fixed \(\ell \ge 6\) 6 , \(\textrm{f}_\textrm{max}(\ell , \Sigma )=\Theta (g)\) f max ( , Σ ) = Θ ( g ) , where g is the genus of \(\Sigma \) Σ .