---
_id: '63383'
abstract:
- lang: eng
  text: "<p>This paper is concerned with radially symmetric solutions of the parabolic-elliptic
    version of the Keller-Segel system with flux limitation, as given by <disp-formula
    content-type=\"math/mathml\">\r\n<mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\"
    alttext=\"StartLayout 1st Row  with Label left-parenthesis reverse-solidus star
    right-parenthesis EndLabel StartLayout Enlarged left-brace 1st Row  u Subscript
    t Baseline equals nabla dot left-parenthesis StartFraction u nabla u Over StartRoot
    u squared plus StartAbsoluteValue nabla u EndAbsoluteValue squared EndRoot EndFraction
    right-parenthesis minus chi nabla dot left-parenthesis StartFraction u nabla v
    Over StartRoot 1 plus StartAbsoluteValue nabla v EndAbsoluteValue squared EndRoot
    EndFraction right-parenthesis comma 2nd Row  0 equals normal upper Delta v minus
    mu plus u comma EndLayout EndLayout\">\r\n  <mml:semantics>\r\n    <mml:mtable
    side=\"left\" displaystyle=\"false\">\r\n      <mml:mlabeledtr>\r\n        <mml:mtd>\r\n
    \         <mml:mtext>(\\star)</mml:mtext>\r\n        </mml:mtd>\r\n        <mml:mtd>\r\n
    \         <mml:mrow>\r\n            <mml:mo>{</mml:mo>\r\n            <mml:mtable
    columnalign=\"left left\" rowspacing=\"0.5em 0.2em\" columnspacing=\"1em\" displaystyle=\"false\">\r\n
    \             <mml:mtr>\r\n                <mml:mtd>\r\n                  <mml:msub>\r\n
    \                   <mml:mi>u</mml:mi>\r\n                    <mml:mi>t</mml:mi>\r\n
    \                 </mml:msub>\r\n                  <mml:mo>=</mml:mo>\r\n                  <mml:mi
    mathvariant=\"normal\">∇<!-- ∇ --></mml:mi>\r\n                  <mml:mo>⋅<!--
    ⋅ --></mml:mo>\r\n                  <mml:mstyle scriptlevel=\"0\">\r\n                    <mml:mrow
    class=\"MJX-TeXAtom-ORD\">\r\n                      <mml:mo maxsize=\"1.623em\"
    minsize=\"1.623em\">(</mml:mo>\r\n                    </mml:mrow>\r\n                  </mml:mstyle>\r\n
    \                 <mml:mfrac>\r\n                    <mml:mrow>\r\n                      <mml:mi>u</mml:mi>\r\n
    \                     <mml:mi mathvariant=\"normal\">∇<!-- ∇ --></mml:mi>\r\n
    \                     <mml:mi>u</mml:mi>\r\n                    </mml:mrow>\r\n
    \                   <mml:msqrt>\r\n                      <mml:msup>\r\n                        <mml:mi>u</mml:mi>\r\n
    \                       <mml:mn>2</mml:mn>\r\n                      </mml:msup>\r\n
    \                     <mml:mo>+</mml:mo>\r\n                      <mml:mrow class=\"MJX-TeXAtom-ORD\">\r\n
    \                       <mml:mo stretchy=\"false\">|</mml:mo>\r\n                      </mml:mrow>\r\n
    \                     <mml:mi mathvariant=\"normal\">∇<!-- ∇ --></mml:mi>\r\n
    \                     <mml:mi>u</mml:mi>\r\n                      <mml:msup>\r\n
    \                       <mml:mrow class=\"MJX-TeXAtom-ORD\">\r\n                          <mml:mo
    stretchy=\"false\">|</mml:mo>\r\n                        </mml:mrow>\r\n                        <mml:mn>2</mml:mn>\r\n
    \                     </mml:msup>\r\n                    </mml:msqrt>\r\n                  </mml:mfrac>\r\n
    \                 <mml:mstyle scriptlevel=\"0\">\r\n                    <mml:mrow
    class=\"MJX-TeXAtom-ORD\">\r\n                      <mml:mo maxsize=\"1.623em\"
    minsize=\"1.623em\">)</mml:mo>\r\n                    </mml:mrow>\r\n                  </mml:mstyle>\r\n
    \                 <mml:mo>−<!-- − --></mml:mo>\r\n                  <mml:mi>χ<!--
    χ --></mml:mi>\r\n                  <mml:mspace width=\"thinmathspace\" />\r\n
    \                 <mml:mi mathvariant=\"normal\">∇<!-- ∇ --></mml:mi>\r\n                  <mml:mo>⋅<!--
    ⋅ --></mml:mo>\r\n                  <mml:mstyle scriptlevel=\"0\">\r\n                    <mml:mrow
    class=\"MJX-TeXAtom-ORD\">\r\n                      <mml:mo maxsize=\"1.623em\"
    minsize=\"1.623em\">(</mml:mo>\r\n                    </mml:mrow>\r\n                  </mml:mstyle>\r\n
    \                 <mml:mfrac>\r\n                    <mml:mrow>\r\n                      <mml:mi>u</mml:mi>\r\n
    \                     <mml:mi mathvariant=\"normal\">∇<!-- ∇ --></mml:mi>\r\n
    \                     <mml:mi>v</mml:mi>\r\n                    </mml:mrow>\r\n
    \                   <mml:msqrt>\r\n                      <mml:mn>1</mml:mn>\r\n
    \                     <mml:mo>+</mml:mo>\r\n                      <mml:mrow class=\"MJX-TeXAtom-ORD\">\r\n
    \                       <mml:mo stretchy=\"false\">|</mml:mo>\r\n                      </mml:mrow>\r\n
    \                     <mml:mi mathvariant=\"normal\">∇<!-- ∇ --></mml:mi>\r\n
    \                     <mml:mi>v</mml:mi>\r\n                      <mml:msup>\r\n
    \                       <mml:mrow class=\"MJX-TeXAtom-ORD\">\r\n                          <mml:mo
    stretchy=\"false\">|</mml:mo>\r\n                        </mml:mrow>\r\n                        <mml:mn>2</mml:mn>\r\n
    \                     </mml:msup>\r\n                    </mml:msqrt>\r\n                  </mml:mfrac>\r\n
    \                 <mml:mstyle scriptlevel=\"0\">\r\n                    <mml:mrow
    class=\"MJX-TeXAtom-ORD\">\r\n                      <mml:mo maxsize=\"1.623em\"
    minsize=\"1.623em\">)</mml:mo>\r\n                    </mml:mrow>\r\n                  </mml:mstyle>\r\n
    \                 <mml:mo>,</mml:mo>\r\n                </mml:mtd>\r\n              </mml:mtr>\r\n
    \             <mml:mtr>\r\n                <mml:mtd>\r\n                  <mml:mn>0</mml:mn>\r\n
    \                 <mml:mo>=</mml:mo>\r\n                  <mml:mi mathvariant=\"normal\">Δ<!--
    Δ --></mml:mi>\r\n                  <mml:mi>v</mml:mi>\r\n                  <mml:mo>−<!--
    − --></mml:mo>\r\n                  <mml:mi>μ<!-- μ --></mml:mi>\r\n                  <mml:mo>+</mml:mo>\r\n
    \                 <mml:mi>u</mml:mi>\r\n                  <mml:mo>,</mml:mo>\r\n
    \               </mml:mtd>\r\n              </mml:mtr>\r\n            </mml:mtable>\r\n
    \           <mml:mo fence=\"true\" stretchy=\"true\" symmetric=\"true\" />\r\n
    \         </mml:mrow>\r\n        </mml:mtd>\r\n      </mml:mlabeledtr>\r\n    </mml:mtable>\r\n
    \   <mml:annotation encoding=\"application/x-tex\">\\begin{equation}\\tag {\\star
    } \\begin {cases} u_t=\\nabla \\cdot \\Big (\\frac {u\\nabla u}{\\sqrt {u^2+|\\nabla
    u|^2}}\\Big ) - \\chi \\, \\nabla \\cdot \\Big (\\frac {u\\nabla v}{\\sqrt {1+|\\nabla
    v|^2}}\\Big ), \\\\[3pt] 0=\\Delta v - \\mu + u, \\end{cases} \\end{equation}</mml:annotation>\r\n
    \ </mml:semantics>\r\n</mml:math>\r\n</disp-formula>\r\n under the initial condition
    <inline-formula content-type=\"math/mathml\">\r\n<mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\"
    alttext=\"u vertical-bar Subscript t equals 0 Baseline equals u 0 greater-than
    0\">\r\n  <mml:semantics>\r\n    <mml:mrow>\r\n      <mml:mi>u</mml:mi>\r\n      <mml:msub>\r\n
    \       <mml:mrow class=\"MJX-TeXAtom-ORD\">\r\n          <mml:mo stretchy=\"false\">|</mml:mo>\r\n
    \       </mml:mrow>\r\n        <mml:mrow class=\"MJX-TeXAtom-ORD\">\r\n          <mml:mi>t</mml:mi>\r\n
    \         <mml:mo>=</mml:mo>\r\n          <mml:mn>0</mml:mn>\r\n        </mml:mrow>\r\n
    \     </mml:msub>\r\n      <mml:mo>=</mml:mo>\r\n      <mml:msub>\r\n        <mml:mi>u</mml:mi>\r\n
    \       <mml:mn>0</mml:mn>\r\n      </mml:msub>\r\n      <mml:mo>&gt;</mml:mo>\r\n
    \     <mml:mn>0</mml:mn>\r\n    </mml:mrow>\r\n    <mml:annotation encoding=\"application/x-tex\">u|_{t=0}=u_0&gt;0</mml:annotation>\r\n
    \ </mml:semantics>\r\n</mml:math>\r\n</inline-formula> and no-flux boundary conditions
    in a ball <inline-formula content-type=\"math/mathml\">\r\n<mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\"
    alttext=\"normal upper Omega subset-of double-struck upper R Superscript n\">\r\n
    \ <mml:semantics>\r\n    <mml:mrow>\r\n      <mml:mi mathvariant=\"normal\">Ω<!--
    Ω --></mml:mi>\r\n      <mml:mo>⊂<!-- ⊂ --></mml:mo>\r\n      <mml:msup>\r\n        <mml:mrow
    class=\"MJX-TeXAtom-ORD\">\r\n          <mml:mi mathvariant=\"double-struck\">R</mml:mi>\r\n
    \       </mml:mrow>\r\n        <mml:mi>n</mml:mi>\r\n      </mml:msup>\r\n    </mml:mrow>\r\n
    \   <mml:annotation encoding=\"application/x-tex\">\\Omega \\subset \\mathbb {R}^n</mml:annotation>\r\n
    \ </mml:semantics>\r\n</mml:math>\r\n</inline-formula>, where <inline-formula
    content-type=\"math/mathml\">\r\n<mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\"
    alttext=\"chi greater-than 0\">\r\n  <mml:semantics>\r\n    <mml:mrow>\r\n      <mml:mi>χ<!--
    χ --></mml:mi>\r\n      <mml:mo>&gt;</mml:mo>\r\n      <mml:mn>0</mml:mn>\r\n
    \   </mml:mrow>\r\n    <mml:annotation encoding=\"application/x-tex\">\\chi &gt;0</mml:annotation>\r\n
    \ </mml:semantics>\r\n</mml:math>\r\n</inline-formula> and <inline-formula content-type=\"math/mathml\">\r\n<mml:math
    xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" alttext=\"mu colon equals StartFraction
    1 Over StartAbsoluteValue normal upper Omega EndAbsoluteValue EndFraction integral
    Underscript normal upper Omega Endscripts u 0\">\r\n  <mml:semantics>\r\n    <mml:mrow>\r\n
    \     <mml:mi>μ<!-- μ --></mml:mi>\r\n      <mml:mo>:=</mml:mo>\r\n      <mml:mfrac>\r\n
    \       <mml:mn>1</mml:mn>\r\n        <mml:mrow>\r\n          <mml:mrow class=\"MJX-TeXAtom-ORD\">\r\n
    \           <mml:mo stretchy=\"false\">|</mml:mo>\r\n          </mml:mrow>\r\n
    \         <mml:mi mathvariant=\"normal\">Ω<!-- Ω --></mml:mi>\r\n          <mml:mrow
    class=\"MJX-TeXAtom-ORD\">\r\n            <mml:mo stretchy=\"false\">|</mml:mo>\r\n
    \         </mml:mrow>\r\n        </mml:mrow>\r\n      </mml:mfrac>\r\n      <mml:msub>\r\n
    \       <mml:mo>∫<!-- ∫ --></mml:mo>\r\n        <mml:mi mathvariant=\"normal\">Ω<!--
    Ω --></mml:mi>\r\n      </mml:msub>\r\n      <mml:msub>\r\n        <mml:mi>u</mml:mi>\r\n
    \       <mml:mn>0</mml:mn>\r\n      </mml:msub>\r\n    </mml:mrow>\r\n    <mml:annotation
    encoding=\"application/x-tex\">\\mu :=\\frac {1}{|\\Omega |} \\int _\\Omega u_0</mml:annotation>\r\n
    \ </mml:semantics>\r\n</mml:math>\r\n</inline-formula>. A previous result of the
    authors [Comm. Partial Differential Equations 42 (2017), 436–473] has asserted
    global existence of bounded classical solutions for arbitrary positive radial
    initial data <inline-formula content-type=\"math/mathml\">\r\n<mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\"
    alttext=\"u 0 element-of upper C cubed left-parenthesis normal upper Omega overbar
    right-parenthesis\">\r\n  <mml:semantics>\r\n    <mml:mrow>\r\n      <mml:msub>\r\n
    \       <mml:mi>u</mml:mi>\r\n        <mml:mn>0</mml:mn>\r\n      </mml:msub>\r\n
    \     <mml:mo>∈<!-- ∈ --></mml:mo>\r\n      <mml:msup>\r\n        <mml:mi>C</mml:mi>\r\n
    \       <mml:mn>3</mml:mn>\r\n      </mml:msup>\r\n      <mml:mo stretchy=\"false\">(</mml:mo>\r\n
    \     <mml:mrow class=\"MJX-TeXAtom-ORD\">\r\n        <mml:mover>\r\n          <mml:mi
    mathvariant=\"normal\">Ω<!-- Ω --></mml:mi>\r\n          <mml:mo stretchy=\"false\">¯<!--
    ¯ --></mml:mo>\r\n        </mml:mover>\r\n      </mml:mrow>\r\n      <mml:mo stretchy=\"false\">)</mml:mo>\r\n
    \   </mml:mrow>\r\n    <mml:annotation encoding=\"application/x-tex\">u_0\\in
    C^3(\\bar \\Omega )</mml:annotation>\r\n  </mml:semantics>\r\n</mml:math>\r\n</inline-formula>
    when either <inline-formula content-type=\"math/mathml\">\r\n<mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\"
    alttext=\"n greater-than-or-equal-to 2\">\r\n  <mml:semantics>\r\n    <mml:mrow>\r\n
    \     <mml:mi>n</mml:mi>\r\n      <mml:mo>≥<!-- ≥ --></mml:mo>\r\n      <mml:mn>2</mml:mn>\r\n
    \   </mml:mrow>\r\n    <mml:annotation encoding=\"application/x-tex\">n\\ge 2</mml:annotation>\r\n
    \ </mml:semantics>\r\n</mml:math>\r\n</inline-formula> and <inline-formula content-type=\"math/mathml\">\r\n<mml:math
    xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" alttext=\"chi greater-than 1\">\r\n
    \ <mml:semantics>\r\n    <mml:mrow>\r\n      <mml:mi>χ<!-- χ --></mml:mi>\r\n
    \     <mml:mo>&gt;</mml:mo>\r\n      <mml:mn>1</mml:mn>\r\n    </mml:mrow>\r\n
    \   <mml:annotation encoding=\"application/x-tex\">\\chi &gt;1</mml:annotation>\r\n
    \ </mml:semantics>\r\n</mml:math>\r\n</inline-formula>, or <inline-formula content-type=\"math/mathml\">\r\n<mml:math
    xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" alttext=\"n equals 1\">\r\n  <mml:semantics>\r\n
    \   <mml:mrow>\r\n      <mml:mi>n</mml:mi>\r\n      <mml:mo>=</mml:mo>\r\n      <mml:mn>1</mml:mn>\r\n
    \   </mml:mrow>\r\n    <mml:annotation encoding=\"application/x-tex\">n=1</mml:annotation>\r\n
    \ </mml:semantics>\r\n</mml:math>\r\n</inline-formula> and <inline-formula content-type=\"math/mathml\">\r\n<mml:math
    xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" alttext=\"integral Underscript
    normal upper Omega Endscripts u 0 greater-than StartFraction 1 Over StartRoot
    left-parenthesis chi squared minus 1 right-parenthesis Subscript plus Baseline
    EndRoot EndFraction\">\r\n  <mml:semantics>\r\n    <mml:mrow>\r\n      <mml:msub>\r\n
    \       <mml:mo>∫<!-- ∫ --></mml:mo>\r\n        <mml:mi mathvariant=\"normal\">Ω<!--
    Ω --></mml:mi>\r\n      </mml:msub>\r\n      <mml:msub>\r\n        <mml:mi>u</mml:mi>\r\n
    \       <mml:mn>0</mml:mn>\r\n      </mml:msub>\r\n      <mml:mo>&gt;</mml:mo>\r\n
    \     <mml:mfrac>\r\n        <mml:mn>1</mml:mn>\r\n        <mml:msqrt>\r\n          <mml:mo
    stretchy=\"false\">(</mml:mo>\r\n          <mml:msup>\r\n            <mml:mi>χ<!--
    χ --></mml:mi>\r\n            <mml:mn>2</mml:mn>\r\n          </mml:msup>\r\n
    \         <mml:mo>−<!-- − --></mml:mo>\r\n          <mml:mn>1</mml:mn>\r\n          <mml:msub>\r\n
    \           <mml:mo stretchy=\"false\">)</mml:mo>\r\n            <mml:mo>+</mml:mo>\r\n
    \         </mml:msub>\r\n        </mml:msqrt>\r\n      </mml:mfrac>\r\n    </mml:mrow>\r\n
    \   <mml:annotation encoding=\"application/x-tex\">\\int _\\Omega u_0&gt;\\frac
    {1}{\\sqrt {(\\chi ^2-1)_+}}</mml:annotation>\r\n  </mml:semantics>\r\n</mml:math>\r\n</inline-formula>.</p>\r\n\r\n<p>This
    present paper shows that these conditions are essentially optimal: Indeed, it
    is shown that if the taxis coefficient satisfies <inline-formula content-type=\"math/mathml\">\r\n<mml:math
    xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" alttext=\"chi greater-than 1\">\r\n
    \ <mml:semantics>\r\n    <mml:mrow>\r\n      <mml:mi>χ<!-- χ --></mml:mi>\r\n
    \     <mml:mo>&gt;</mml:mo>\r\n      <mml:mn>1</mml:mn>\r\n    </mml:mrow>\r\n
    \   <mml:annotation encoding=\"application/x-tex\">\\chi &gt;1</mml:annotation>\r\n
    \ </mml:semantics>\r\n</mml:math>\r\n</inline-formula>, then for any choice of
    <disp-formula content-type=\"math/mathml\">\r\n\\[\r\n<mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\"
    alttext=\"StartLayout Enlarged left-brace 1st Row 1st Column m greater-than StartFraction
    1 Over StartRoot chi squared minus 1 EndRoot EndFraction 2nd Column a m p semicolon
    if n equals 1 comma 2nd Row 1st Column m greater-than 0 is arbitrary 2nd Column
    a m p semicolon if n greater-than-or-equal-to 2 comma EndLayout\">\r\n  <mml:semantics>\r\n
    \   <mml:mrow>\r\n      <mml:mo>{</mml:mo>\r\n      <mml:mtable columnalign=\"left
    left\" rowspacing=\".2em\" columnspacing=\"1em\" displaystyle=\"false\">\r\n        <mml:mtr>\r\n
    \         <mml:mtd>\r\n            <mml:mi>m</mml:mi>\r\n            <mml:mo>&gt;</mml:mo>\r\n
    \           <mml:mfrac>\r\n              <mml:mn>1</mml:mn>\r\n              <mml:msqrt>\r\n
    \               <mml:msup>\r\n                  <mml:mi>χ<!-- χ --></mml:mi>\r\n
    \                 <mml:mn>2</mml:mn>\r\n                </mml:msup>\r\n                <mml:mo>−<!--
    − --></mml:mo>\r\n                <mml:mn>1</mml:mn>\r\n              </mml:msqrt>\r\n
    \           </mml:mfrac>\r\n          </mml:mtd>\r\n          <mml:mtd>\r\n            <mml:mi>a</mml:mi>\r\n
    \           <mml:mi>m</mml:mi>\r\n            <mml:mi>p</mml:mi>\r\n            <mml:mo>;</mml:mo>\r\n
    \           <mml:mrow>\r\n              <mml:mtext>if </mml:mtext>\r\n              <mml:mrow
    class=\"MJX-TeXAtom-ORD\">\r\n                <mml:mi>n</mml:mi>\r\n                <mml:mo>=</mml:mo>\r\n
    \               <mml:mn>1</mml:mn>\r\n              </mml:mrow>\r\n            </mml:mrow>\r\n
    \           <mml:mo>,</mml:mo>\r\n          </mml:mtd>\r\n        </mml:mtr>\r\n
    \       <mml:mtr>\r\n          <mml:mtd>\r\n            <mml:mrow>\r\n              <mml:mrow
    class=\"MJX-TeXAtom-ORD\">\r\n                <mml:mi>m</mml:mi>\r\n                <mml:mo>&gt;</mml:mo>\r\n
    \               <mml:mn>0</mml:mn>\r\n              </mml:mrow>\r\n              <mml:mtext> is
    arbitrary</mml:mtext>\r\n            </mml:mrow>\r\n          </mml:mtd>\r\n          <mml:mtd>\r\n
    \           <mml:mi>a</mml:mi>\r\n            <mml:mi>m</mml:mi>\r\n            <mml:mi>p</mml:mi>\r\n
    \           <mml:mo>;</mml:mo>\r\n            <mml:mrow>\r\n              <mml:mtext>if </mml:mtext>\r\n
    \             <mml:mrow class=\"MJX-TeXAtom-ORD\">\r\n                <mml:mi>n</mml:mi>\r\n
    \               <mml:mo>≥<!-- ≥ --></mml:mo>\r\n                <mml:mn>2</mml:mn>\r\n
    \             </mml:mrow>\r\n            </mml:mrow>\r\n            <mml:mo>,</mml:mo>\r\n
    \         </mml:mtd>\r\n        </mml:mtr>\r\n      </mml:mtable>\r\n      <mml:mo
    fence=\"true\" stretchy=\"true\" symmetric=\"true\" />\r\n    </mml:mrow>\r\n
    \   <mml:annotation encoding=\"application/x-tex\">\\begin {cases} m&gt;\\frac
    {1}{\\sqrt {\\chi ^2-1}} &amp; \\text {if $n=1$}, \\\\ \\text {$m&gt;0$ is arbitrary}
    &amp; \\text {if $n\\ge 2$}, \\end {cases}</mml:annotation>\r\n  </mml:semantics>\r\n</mml:math>\r\n\\]\r\n</disp-formula>
    there exist positive initial data <inline-formula content-type=\"math/mathml\">\r\n<mml:math
    xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" alttext=\"u 0 element-of upper
    C cubed left-parenthesis normal upper Omega overbar right-parenthesis\">\r\n  <mml:semantics>\r\n
    \   <mml:mrow>\r\n      <mml:msub>\r\n        <mml:mi>u</mml:mi>\r\n        <mml:mn>0</mml:mn>\r\n
    \     </mml:msub>\r\n      <mml:mo>∈<!-- ∈ --></mml:mo>\r\n      <mml:msup>\r\n
    \       <mml:mi>C</mml:mi>\r\n        <mml:mn>3</mml:mn>\r\n      </mml:msup>\r\n
    \     <mml:mo stretchy=\"false\">(</mml:mo>\r\n      <mml:mrow class=\"MJX-TeXAtom-ORD\">\r\n
    \       <mml:mover>\r\n          <mml:mi mathvariant=\"normal\">Ω<!-- Ω --></mml:mi>\r\n
    \         <mml:mo stretchy=\"false\">¯<!-- ¯ --></mml:mo>\r\n        </mml:mover>\r\n
    \     </mml:mrow>\r\n      <mml:mo stretchy=\"false\">)</mml:mo>\r\n    </mml:mrow>\r\n
    \   <mml:annotation encoding=\"application/x-tex\">u_0\\in C^3(\\bar \\Omega )</mml:annotation>\r\n
    \ </mml:semantics>\r\n</mml:math>\r\n</inline-formula> satisfying <inline-formula
    content-type=\"math/mathml\">\r\n<mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\"
    alttext=\"integral Underscript normal upper Omega Endscripts u 0 equals m\">\r\n
    \ <mml:semantics>\r\n    <mml:mrow>\r\n      <mml:msub>\r\n        <mml:mo>∫<!--
    ∫ --></mml:mo>\r\n        <mml:mi mathvariant=\"normal\">Ω<!-- Ω --></mml:mi>\r\n
    \     </mml:msub>\r\n      <mml:msub>\r\n        <mml:mi>u</mml:mi>\r\n        <mml:mn>0</mml:mn>\r\n
    \     </mml:msub>\r\n      <mml:mo>=</mml:mo>\r\n      <mml:mi>m</mml:mi>\r\n
    \   </mml:mrow>\r\n    <mml:annotation encoding=\"application/x-tex\">\\int _\\Omega
    u_0=m</mml:annotation>\r\n  </mml:semantics>\r\n</mml:math>\r\n</inline-formula>
    which are such that for some <inline-formula content-type=\"math/mathml\">\r\n<mml:math
    xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" alttext=\"upper T greater-than
    0\">\r\n  <mml:semantics>\r\n    <mml:mrow>\r\n      <mml:mi>T</mml:mi>\r\n      <mml:mo>&gt;</mml:mo>\r\n
    \     <mml:mn>0</mml:mn>\r\n    </mml:mrow>\r\n    <mml:annotation encoding=\"application/x-tex\">T&gt;0</mml:annotation>\r\n
    \ </mml:semantics>\r\n</mml:math>\r\n</inline-formula>, (<inline-formula content-type=\"math/mathml\">\r\n<mml:math
    xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" alttext=\"star\">\r\n  <mml:semantics>\r\n
    \   <mml:mo>⋆<!-- ⋆ --></mml:mo>\r\n    <mml:annotation encoding=\"application/x-tex\">\\star</mml:annotation>\r\n
    \ </mml:semantics>\r\n</mml:math>\r\n</inline-formula>) possesses a uniquely determined
    classical solution <inline-formula content-type=\"math/mathml\">\r\n<mml:math
    xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" alttext=\"left-parenthesis u
    comma v right-parenthesis\">\r\n  <mml:semantics>\r\n    <mml:mrow>\r\n      <mml:mo
    stretchy=\"false\">(</mml:mo>\r\n      <mml:mi>u</mml:mi>\r\n      <mml:mo>,</mml:mo>\r\n
    \     <mml:mi>v</mml:mi>\r\n      <mml:mo stretchy=\"false\">)</mml:mo>\r\n    </mml:mrow>\r\n
    \   <mml:annotation encoding=\"application/x-tex\">(u,v)</mml:annotation>\r\n
    \ </mml:semantics>\r\n</mml:math>\r\n</inline-formula> in <inline-formula content-type=\"math/mathml\">\r\n<mml:math
    xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" alttext=\"normal upper Omega
    times left-parenthesis 0 comma upper T right-parenthesis\">\r\n  <mml:semantics>\r\n
    \   <mml:mrow>\r\n      <mml:mi mathvariant=\"normal\">Ω<!-- Ω --></mml:mi>\r\n
    \     <mml:mo>×<!-- × --></mml:mo>\r\n      <mml:mo stretchy=\"false\">(</mml:mo>\r\n
    \     <mml:mn>0</mml:mn>\r\n      <mml:mo>,</mml:mo>\r\n      <mml:mi>T</mml:mi>\r\n
    \     <mml:mo stretchy=\"false\">)</mml:mo>\r\n    </mml:mrow>\r\n    <mml:annotation
    encoding=\"application/x-tex\">\\Omega \\times (0,T)</mml:annotation>\r\n  </mml:semantics>\r\n</mml:math>\r\n</inline-formula>
    blowing up at time <inline-formula content-type=\"math/mathml\">\r\n<mml:math
    xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" alttext=\"upper T\">\r\n  <mml:semantics>\r\n
    \   <mml:mi>T</mml:mi>\r\n    <mml:annotation encoding=\"application/x-tex\">T</mml:annotation>\r\n
    \ </mml:semantics>\r\n</mml:math>\r\n</inline-formula> in the sense that <inline-formula
    content-type=\"math/mathml\">\r\n<mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\"
    alttext=\"limit sup double-vertical-bar u left-parenthesis dot comma t right-parenthesis
    double-vertical-bar Subscript upper L Sub Superscript normal infinity Subscript
    left-parenthesis normal upper Omega right-parenthesis Baseline equals normal infinity\">\r\n
    \ <mml:semantics>\r\n    <mml:mrow>\r\n      <mml:munder>\r\n        <mml:mo movablelimits=\"true\"
    form=\"prefix\">lim sup</mml:mo>\r\n        <mml:mrow class=\"MJX-TeXAtom-ORD\">\r\n
    \         <mml:mi>t</mml:mi>\r\n          <mml:mo stretchy=\"false\">↗<!-- ↗ --></mml:mo>\r\n
    \         <mml:mi>T</mml:mi>\r\n        </mml:mrow>\r\n      </mml:munder>\r\n
    \     <mml:mo fence=\"false\" stretchy=\"false\">‖<!-- ‖ --></mml:mo>\r\n      <mml:mi>u</mml:mi>\r\n
    \     <mml:mo stretchy=\"false\">(</mml:mo>\r\n      <mml:mo>⋅<!-- ⋅ --></mml:mo>\r\n
    \     <mml:mo>,</mml:mo>\r\n      <mml:mi>t</mml:mi>\r\n      <mml:mo stretchy=\"false\">)</mml:mo>\r\n
    \     <mml:msub>\r\n        <mml:mo fence=\"false\" stretchy=\"false\">‖<!-- ‖
    --></mml:mo>\r\n        <mml:mrow class=\"MJX-TeXAtom-ORD\">\r\n          <mml:msup>\r\n
    \           <mml:mi>L</mml:mi>\r\n            <mml:mi mathvariant=\"normal\">∞<!--
    ∞ --></mml:mi>\r\n          </mml:msup>\r\n          <mml:mo stretchy=\"false\">(</mml:mo>\r\n
    \         <mml:mi mathvariant=\"normal\">Ω<!-- Ω --></mml:mi>\r\n          <mml:mo
    stretchy=\"false\">)</mml:mo>\r\n        </mml:mrow>\r\n      </mml:msub>\r\n
    \     <mml:mo>=</mml:mo>\r\n      <mml:mi mathvariant=\"normal\">∞<!-- ∞ --></mml:mi>\r\n
    \   </mml:mrow>\r\n    <mml:annotation encoding=\"application/x-tex\">\\limsup
    _{t\\nearrow T} \\|u(\\cdot ,t)\\|_{L^\\infty (\\Omega )}=\\infty</mml:annotation>\r\n
    \ </mml:semantics>\r\n</mml:math>\r\n</inline-formula>.</p>\r\n\r\n<p>This result
    is derived by means of a comparison argument applied to the doubly degenerate
    scalar parabolic equation satisfied by the mass accumulation function associated
    with (<inline-formula content-type=\"math/mathml\">\r\n<mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\"
    alttext=\"star\">\r\n  <mml:semantics>\r\n    <mml:mo>⋆<!-- ⋆ --></mml:mo>\r\n
    \   <mml:annotation encoding=\"application/x-tex\">\\star</mml:annotation>\r\n
    \ </mml:semantics>\r\n</mml:math>\r\n</inline-formula>).</p>"
author:
- first_name: Nicola
  full_name: Bellomo, Nicola
  last_name: Bellomo
- first_name: Michael
  full_name: Winkler, Michael
  id: '31496'
  last_name: Winkler
citation:
  ama: Bellomo N, Winkler M. Finite-time blow-up in a degenerate chemotaxis system
    with flux limitation. <i>Transactions of the American Mathematical Society, Series
    B</i>. 2017;4(2):31-67. doi:<a href="https://doi.org/10.1090/btran/17">10.1090/btran/17</a>
  apa: Bellomo, N., &#38; Winkler, M. (2017). Finite-time blow-up in a degenerate
    chemotaxis system with flux limitation. <i>Transactions of the American Mathematical
    Society, Series B</i>, <i>4</i>(2), 31–67. <a href="https://doi.org/10.1090/btran/17">https://doi.org/10.1090/btran/17</a>
  bibtex: '@article{Bellomo_Winkler_2017, title={Finite-time blow-up in a degenerate
    chemotaxis system with flux limitation}, volume={4}, DOI={<a href="https://doi.org/10.1090/btran/17">10.1090/btran/17</a>},
    number={2}, journal={Transactions of the American Mathematical Society, Series
    B}, publisher={American Mathematical Society (AMS)}, author={Bellomo, Nicola and
    Winkler, Michael}, year={2017}, pages={31–67} }'
  chicago: 'Bellomo, Nicola, and Michael Winkler. “Finite-Time Blow-up in a Degenerate
    Chemotaxis System with Flux Limitation.” <i>Transactions of the American Mathematical
    Society, Series B</i> 4, no. 2 (2017): 31–67. <a href="https://doi.org/10.1090/btran/17">https://doi.org/10.1090/btran/17</a>.'
  ieee: 'N. Bellomo and M. Winkler, “Finite-time blow-up in a degenerate chemotaxis
    system with flux limitation,” <i>Transactions of the American Mathematical Society,
    Series B</i>, vol. 4, no. 2, pp. 31–67, 2017, doi: <a href="https://doi.org/10.1090/btran/17">10.1090/btran/17</a>.'
  mla: Bellomo, Nicola, and Michael Winkler. “Finite-Time Blow-up in a Degenerate
    Chemotaxis System with Flux Limitation.” <i>Transactions of the American Mathematical
    Society, Series B</i>, vol. 4, no. 2, American Mathematical Society (AMS), 2017,
    pp. 31–67, doi:<a href="https://doi.org/10.1090/btran/17">10.1090/btran/17</a>.
  short: N. Bellomo, M. Winkler, Transactions of the American Mathematical Society,
    Series B 4 (2017) 31–67.
date_created: 2025-12-19T11:09:53Z
date_updated: 2025-12-19T11:10:17Z
doi: 10.1090/btran/17
intvolume: '         4'
issue: '2'
language:
- iso: eng
page: 31-67
publication: Transactions of the American Mathematical Society, Series B
publication_identifier:
  issn:
  - 2330-0000
publication_status: published
publisher: American Mathematical Society (AMS)
status: public
title: Finite-time blow-up in a degenerate chemotaxis system with flux limitation
type: journal_article
user_id: '31496'
volume: 4
year: '2017'
...
