[{"title":"Finite-time blow-up in a degenerate chemotaxis system with flux limitation","doi":"10.1090/btran/17","publisher":"American Mathematical Society (AMS)","date_updated":"2025-12-19T11:10:17Z","author":[{"first_name":"Nicola","last_name":"Bellomo","full_name":"Bellomo, Nicola"},{"first_name":"Michael","last_name":"Winkler","id":"31496","full_name":"Winkler, Michael"}],"date_created":"2025-12-19T11:09:53Z","volume":4,"year":"2017","citation":{"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} }","short":"N. Bellomo, M. Winkler, Transactions of the American Mathematical Society, Series B 4 (2017) 31–67.","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>.","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>","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>.","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>."},"page":"31-67","intvolume":"         4","publication_status":"published","publication_identifier":{"issn":["2330-0000"]},"issue":"2","language":[{"iso":"eng"}],"_id":"63383","user_id":"31496","abstract":[{"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>","lang":"eng"}],"status":"public","type":"journal_article","publication":"Transactions of the American Mathematical Society, Series B"}]
