<p>This paper deals with a food chain model with density dependence as follows: <Equation ID="Equ101"> <EquationSource Format="TEX">\(\begin{aligned} {\left\{ \begin{array}{ll} u_t=\Delta u+u(1-u)-b_1uv,&amp; \quad x\in \Omega ,t&gt;0,\\ v_t=\Delta (\gamma _1(u)v )+uv-b_2vw+\theta _1(v-v^2),&amp; \quad x\in \Omega , t&gt;0,\\ w_t=\Delta (\gamma _2(v)w )+vw+\theta _2(w-w^2), &amp; \quad x\in \Omega ,t&gt;0,\\ \end{array}\right. } \end{aligned}\)</EquationSource> <EquationSource Format="MATHML"><math display="block"> <mrow> <mtable> <mtr> <mtd columnalign="right"> <mfenced open="{"> <mrow> <mtable> <mtr> <mtd columnalign="left"> <mrow> <msub> <mi>u</mi> <mi>t</mi> </msub> <mo>=</mo> <mi mathvariant="normal">Δ</mi> <mi>u</mi> <mo>+</mo> <mi>u</mi> <mrow> <mo stretchy="false">(</mo> <mn>1</mn> <mo>-</mo> <mi>u</mi> <mo stretchy="false">)</mo> </mrow> <mo>-</mo> <msub> <mi>b</mi> <mn>1</mn> </msub> <mi>u</mi> <mi>v</mi> <mo>,</mo> </mrow> </mtd> <mtd columnalign="left"> <mrow> <mspace width="1em" /> <mi>x</mi> <mo>∈</mo> <mi mathvariant="normal">Ω</mi> <mo>,</mo> <mi>t</mi> <mo>&gt;</mo> <mn>0</mn> <mo>,</mo> </mrow> </mtd> </mtr> <mtr> <mtd columnalign="left"> <mrow> <mrow /> <msub> <mi>v</mi> <mi>t</mi> </msub> <mo>=</mo> <mi mathvariant="normal">Δ</mi> <mrow> <mo stretchy="false">(</mo> <msub> <mi>γ</mi> <mn>1</mn> </msub> <mrow> <mo stretchy="false">(</mo> <mi>u</mi> <mo stretchy="false">)</mo> </mrow> <mi>v</mi> <mo stretchy="false">)</mo> </mrow> <mo>+</mo> <mi>u</mi> <mi>v</mi> <mo>-</mo> <msub> <mi>b</mi> <mn>2</mn> </msub> <mi>v</mi> <mi>w</mi> <mo>+</mo> <msub> <mi>θ</mi> <mn>1</mn> </msub> <mrow> <mo stretchy="false">(</mo> <mi>v</mi> <mo>-</mo> <msup> <mi>v</mi> <mn>2</mn> </msup> <mo stretchy="false">)</mo> </mrow> <mo>,</mo> </mrow> </mtd> <mtd columnalign="left"> <mrow> <mspace width="1em" /> <mi>x</mi> <mo>∈</mo> <mi mathvariant="normal">Ω</mi> <mo>,</mo> <mi>t</mi> <mo>&gt;</mo> <mn>0</mn> <mo>,</mo> </mrow> </mtd> </mtr> <mtr> <mtd columnalign="left"> <mrow> <mrow /> <msub> <mi>w</mi> <mi>t</mi> </msub> <mo>=</mo> <mi mathvariant="normal">Δ</mi> <mrow> <mo stretchy="false">(</mo> <msub> <mi>γ</mi> <mn>2</mn> </msub> <mrow> <mo stretchy="false">(</mo> <mi>v</mi> <mo stretchy="false">)</mo> </mrow> <mi>w</mi> <mo stretchy="false">)</mo> </mrow> <mo>+</mo> <mi>v</mi> <mi>w</mi> <mo>+</mo> <msub> <mi>θ</mi> <mn>2</mn> </msub> <mrow> <mo stretchy="false">(</mo> <mi>w</mi> <mo>-</mo> <msup> <mi>w</mi> <mn>2</mn> </msup> <mo stretchy="false">)</mo> </mrow> <mo>,</mo> </mrow> </mtd> <mtd columnalign="left"> <mrow> <mspace width="1em" /> <mi>x</mi> <mo>∈</mo> <mi mathvariant="normal">Ω</mi> <mo>,</mo> <mi>t</mi> <mo>&gt;</mo> <mn>0</mn> <mo>,</mo> </mrow> </mtd> </mtr> </mtable> </mrow> </mfenced> </mtd> </mtr> </mtable> </mrow> </math></EquationSource> </Equation>under homogeneous Neumann boundary conditions in a smooth-bounded domain <InlineEquation ID="IEq1"> <EquationSource Format="TEX">\(\Omega \subset \mathbb {R}^2.\)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mi mathvariant="normal">Ω</mi> <mo>⊂</mo> <msup> <mrow> <mi mathvariant="double-struck">R</mi> </mrow> <mn>2</mn> </msup> <mo>.</mo> </mrow> </math></EquationSource> </InlineEquation> For <InlineEquation ID="IEq2"> <EquationSource Format="TEX">\(i=1,2\)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mi>i</mi> <mo>=</mo> <mn>1</mn> <mo>,</mo> <mn>2</mn> </mrow> </math></EquationSource> </InlineEquation>, the parameters <InlineEquation ID="IEq3"> <EquationSource Format="TEX">\(b_i\)</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mi>b</mi> <mi>i</mi> </msub> </math></EquationSource> </InlineEquation> and <InlineEquation ID="IEq4"> <EquationSource Format="TEX">\(\theta _i\)</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mi>θ</mi> <mi>i</mi> </msub> </math></EquationSource> </InlineEquation> are positive and the function <InlineEquation ID="IEq5"> <EquationSource Format="TEX">\(\gamma _i\)</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mi>γ</mi> <mi>i</mi> </msub> </math></EquationSource> </InlineEquation> satisfies <InlineEquation ID="IEq6"> <EquationSource Format="TEX">\(\gamma _i\in C^3([0,\infty ))\)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <msub> <mi>γ</mi> <mi>i</mi> </msub> <mo>∈</mo> <msup> <mi>C</mi> <mn>3</mn> </msup> <mrow> <mo stretchy="false">(</mo> <mrow> <mo stretchy="false">[</mo> <mn>0</mn> <mo>,</mo> <mi>∞</mi> <mo stretchy="false">)</mo> </mrow> <mo stretchy="false">)</mo> </mrow> </mrow> </math></EquationSource> </InlineEquation> and <InlineEquation ID="IEq7"> <EquationSource Format="TEX">\(\gamma _i(s)&gt;0\)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <msub> <mi>γ</mi> <mi>i</mi> </msub> <mrow> <mo stretchy="false">(</mo> <mi>s</mi> <mo stretchy="false">)</mo> </mrow> <mo>&gt;</mo> <mn>0</mn> </mrow> </math></EquationSource> </InlineEquation> for all <InlineEquation ID="IEq8"> <EquationSource Format="TEX">\(s\ge 0\)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mi>s</mi> <mo>≥</mo> <mn>0</mn> </mrow> </math></EquationSource> </InlineEquation>. It is proved that this system possesses globally bounded classical solutions. Moreover, by constructing Lyapunov functionals, the global stability of the semi-coexistence steady states and the coexistence steady state under suitable conditions on parameters are established.</p>

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Dynamical behavior of food chain models with density-dependent motilities

  • Hang Li,
  • Liangchen Wang

摘要

This paper deals with a food chain model with density dependence as follows: \(\begin{aligned} {\left\{ \begin{array}{ll} u_t=\Delta u+u(1-u)-b_1uv,& \quad x\in \Omega ,t>0,\\ v_t=\Delta (\gamma _1(u)v )+uv-b_2vw+\theta _1(v-v^2),& \quad x\in \Omega , t>0,\\ w_t=\Delta (\gamma _2(v)w )+vw+\theta _2(w-w^2), & \quad x\in \Omega ,t>0,\\ \end{array}\right. } \end{aligned}\) u t = Δ u + u ( 1 - u ) - b 1 u v , x Ω , t > 0 , v t = Δ ( γ 1 ( u ) v ) + u v - b 2 v w + θ 1 ( v - v 2 ) , x Ω , t > 0 , w t = Δ ( γ 2 ( v ) w ) + v w + θ 2 ( w - w 2 ) , x Ω , t > 0 , under homogeneous Neumann boundary conditions in a smooth-bounded domain \(\Omega \subset \mathbb {R}^2.\) Ω R 2 . For \(i=1,2\) i = 1 , 2 , the parameters \(b_i\) b i and \(\theta _i\) θ i are positive and the function \(\gamma _i\) γ i satisfies \(\gamma _i\in C^3([0,\infty ))\) γ i C 3 ( [ 0 , ) ) and \(\gamma _i(s)>0\) γ i ( s ) > 0 for all \(s\ge 0\) s 0 . It is proved that this system possesses globally bounded classical solutions. Moreover, by constructing Lyapunov functionals, the global stability of the semi-coexistence steady states and the coexistence steady state under suitable conditions on parameters are established.