<p>We consider a generalized Ermakov–Pinney equation with indefinite weights <Equation ID="Equ16"> <MediaObject> <ImageObject Color="BlackWhite" FileRef="11784_2025_1197_Article_Equ16.gif" Format="GIF" Height="38" Rendition="HTML" Resolution="72" Type="Linedraw" Width="133" /> </MediaObject> <EquationSource Format="TEX">\(\begin{aligned} x''+a(t)x=\frac{h(t)}{x^\rho }, \end{aligned}\)</EquationSource> <EquationSource Format="MATHML"><math display="block"> <mrow> <mtable> <mtr> <mtd columnalign="right"> <mrow> <msup> <mi>x</mi> <mrow> <mo>′</mo> <mo>′</mo> </mrow> </msup> <mo>+</mo> <mi>a</mi> <mrow> <mo stretchy="false">(</mo> <mi>t</mi> <mo stretchy="false">)</mo> </mrow> <mi>x</mi> <mo>=</mo> <mfrac> <mrow> <mi>h</mi> <mo stretchy="false">(</mo> <mi>t</mi> <mo stretchy="false">)</mo> </mrow> <msup> <mi>x</mi> <mi>ρ</mi> </msup> </mfrac> <mo>,</mo> </mrow> </mtd> </mtr> </mtable> </mrow> </math></EquationSource> </Equation>where <InlineEquation ID="IEq1"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="11784_2025_1197_Article_IEq1.gif" Format="GIF" Height="12" Rendition="HTML" Resolution="72" Type="Linedraw" Width="13" /> </InlineMediaObject> <EquationSource Format="TEX">\(\rho \)</EquationSource> <EquationSource Format="MATHML"><math> <mi>ρ</mi> </math></EquationSource> </InlineEquation> is a real constant and <InlineEquation ID="IEq2"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="11784_2025_1197_Article_IEq2.gif" Format="GIF" Height="16" Rendition="HTML" Resolution="72" Type="Linedraw" Width="42" /> </InlineMediaObject> <EquationSource Format="TEX">\(\rho &gt;0\)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mi>ρ</mi> <mo>&gt;</mo> <mn>0</mn> </mrow> </math></EquationSource> </InlineEquation>, <InlineEquation ID="IEq3"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="11784_2025_1197_Article_IEq3.gif" Format="GIF" Height="19" Rendition="HTML" Resolution="72" Type="Linedraw" Width="132" /> </InlineMediaObject> <EquationSource Format="TEX">\(a,~h\in L^\infty (\mathbb {R}/T\mathbb {Z})\)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mi>a</mi> <mo>,</mo> <mspace width="3.33333pt" /> <mi>h</mi> <mo>∈</mo> <msup> <mi>L</mi> <mi>∞</mi> </msup> <mrow> <mo stretchy="false">(</mo> <mi mathvariant="double-struck">R</mi> <mo stretchy="false">/</mo> <mi>T</mi> <mi mathvariant="double-struck">Z</mi> <mo stretchy="false">)</mo> </mrow> </mrow> </math></EquationSource> </InlineEquation>. Using the positivity of Green’s function and Krasnoselski<InlineEquation ID="IEq4"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="11784_2025_1197_Article_IEq4.gif" Format="GIF" Height="18" Rendition="HTML" Resolution="72" Type="Linedraw" Width="10" /> </InlineMediaObject> <EquationSource Format="TEX">\(\breve{\text{ i }}\)</EquationSource> <EquationSource Format="MATHML"><math> <mover accent="true"> <mrow> <mspace width="0.333333em" /> <mtext>i</mtext> <mspace width="0.333333em" /> </mrow> <mo>˘</mo> </mover> </math></EquationSource> </InlineEquation>’s–Guo fixed point theorem, we give sufficient conditions guaranteeing the existence of at least one positive periodic solution for Ermakov–Pinney equation with indefinite weights. The results are applicable to weak as well as strong singularities.</p>

错误:搜索内容不能为空,请输入英文关键词
错误:关键词超出字数限制,请精简
高级检索

Positive periodic solutions to a generalized Ermakov–Pinney equation with indefinite weights

  • Yun Xin,
  • Zhibo Cheng

摘要

We consider a generalized Ermakov–Pinney equation with indefinite weights \(\begin{aligned} x''+a(t)x=\frac{h(t)}{x^\rho }, \end{aligned}\) x + a ( t ) x = h ( t ) x ρ , where \(\rho \) ρ is a real constant and \(\rho >0\) ρ > 0 , \(a,~h\in L^\infty (\mathbb {R}/T\mathbb {Z})\) a , h L ( R / T Z ) . Using the positivity of Green’s function and Krasnoselski \(\breve{\text{ i }}\) i ˘ ’s–Guo fixed point theorem, we give sufficient conditions guaranteeing the existence of at least one positive periodic solution for Ermakov–Pinney equation with indefinite weights. The results are applicable to weak as well as strong singularities.