<p>In this work we consider the class of partially integrable 3-dimensional piecewise smooth vector fields <InlineEquation ID="IEq1"> <EquationSource Format="TEX">\(Y=(X^+,X^-)\)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mi>Y</mi> <mo>=</mo> <mo stretchy="false">(</mo> <msup> <mi>X</mi> <mo>+</mo> </msup> <mo>,</mo> <msup> <mi>X</mi> <mo>-</mo> </msup> <mo stretchy="false">)</mo> </mrow> </math></EquationSource> </InlineEquation> with separation set <InlineEquation ID="IEq2"> <EquationSource Format="TEX">\(\Sigma =\{(x,y,z)\in {\mathbb {R}}^3: z=0\}\)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mi mathvariant="normal">Σ</mi> <mo>=</mo> <mo stretchy="false">{</mo> <mrow> <mo stretchy="false">(</mo> <mi>x</mi> <mo>,</mo> <mi>y</mi> <mo>,</mo> <mi>z</mi> <mo stretchy="false">)</mo> </mrow> <mo>∈</mo> <msup> <mrow> <mi mathvariant="double-struck">R</mi> </mrow> <mn>3</mn> </msup> <mo>:</mo> <mi>z</mi> <mo>=</mo> <mn>0</mn> <mo stretchy="false">}</mo> </mrow> </math></EquationSource> </InlineEquation> and first integral <InlineEquation ID="IEq3"> <EquationSource Format="TEX">\(H(x,y,z)=x^2+y^2+z^2\)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mi>H</mi> <mrow> <mo stretchy="false">(</mo> <mi>x</mi> <mo>,</mo> <mi>y</mi> <mo>,</mo> <mi>z</mi> <mo stretchy="false">)</mo> </mrow> <mo>=</mo> <msup> <mi>x</mi> <mn>2</mn> </msup> <mo>+</mo> <msup> <mi>y</mi> <mn>2</mn> </msup> <mo>+</mo> <msup> <mi>z</mi> <mn>2</mn> </msup> </mrow> </math></EquationSource> </InlineEquation> that leaves invariant any sphere centered at the origin, <InlineEquation ID="IEq4"> <EquationSource Format="TEX">\({\mathbb {S}}_\rho ^2=\{(x,y,z)\in {\mathbb {R}}^3: x^2+y^2+z^2=\rho ^2\}\)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <msubsup> <mi mathvariant="double-struck">S</mi> <mi>ρ</mi> <mn>2</mn> </msubsup> <mo>=</mo> <mrow> <mo stretchy="false">{</mo> <mrow> <mo stretchy="false">(</mo> <mi>x</mi> <mo>,</mo> <mi>y</mi> <mo>,</mo> <mi>z</mi> <mo stretchy="false">)</mo> </mrow> <mo>∈</mo> <msup> <mrow> <mi mathvariant="double-struck">R</mi> </mrow> <mn>3</mn> </msup> <mo>:</mo> <msup> <mi>x</mi> <mn>2</mn> </msup> <mo>+</mo> <msup> <mi>y</mi> <mn>2</mn> </msup> <mo>+</mo> <msup> <mi>z</mi> <mn>2</mn> </msup> <mo>=</mo> <msup> <mi>ρ</mi> <mn>2</mn> </msup> <mo stretchy="false">}</mo> </mrow> </mrow> </math></EquationSource> </InlineEquation>. We denote this class by <InlineEquation ID="IEq5"> <EquationSource Format="TEX">\(\mathcal {X}\)</EquationSource> <EquationSource Format="MATHML"><math> <mi mathvariant="script">X</mi> </math></EquationSource> </InlineEquation> and by <InlineEquation ID="IEq6"> <EquationSource Format="TEX">\(\mathcal {X}_n\)</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mi mathvariant="script">X</mi> <mi>n</mi> </msub> </math></EquationSource> </InlineEquation> when <InlineEquation ID="IEq7"> <EquationSource Format="TEX">\(X^\pm \)</EquationSource> <EquationSource Format="MATHML"><math> <msup> <mi>X</mi> <mo>±</mo> </msup> </math></EquationSource> </InlineEquation> are polynomial vector fields of degree <i>n</i>. Our main goal is to study piecewise smooth vector fields in the class <InlineEquation ID="IEq8"> <EquationSource Format="TEX">\(\mathcal {X}_1\)</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mi mathvariant="script">X</mi> <mn>1</mn> </msub> </math></EquationSource> </InlineEquation> presenting three periodic annuli on the invariant sphere <InlineEquation ID="IEq9"> <EquationSource Format="TEX">\({\mathbb {S}}_1^2\)</EquationSource> <EquationSource Format="MATHML"><math> <msubsup> <mi mathvariant="double-struck">S</mi> <mn>1</mn> <mn>2</mn> </msubsup> </math></EquationSource> </InlineEquation> proving that there exists a mixed simultaneous configuration with at least five limit cycles bifurcating simultaneously of them, considering polynomial perturbations inside the class <InlineEquation ID="IEq10"> <EquationSource Format="TEX">\(\mathcal {X}_2\)</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mi mathvariant="script">X</mi> <mn>2</mn> </msub> </math></EquationSource> </InlineEquation>.</p>

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Mixed Simultaneous Cyclicity for Piecewise Smooth Vector Fields Defined on an Invariant Sphere

  • Regilene Oliveira,
  • Ana Livia Rodero,
  • Joan Torregrosa

摘要

In this work we consider the class of partially integrable 3-dimensional piecewise smooth vector fields \(Y=(X^+,X^-)\) Y = ( X + , X - ) with separation set \(\Sigma =\{(x,y,z)\in {\mathbb {R}}^3: z=0\}\) Σ = { ( x , y , z ) R 3 : z = 0 } and first integral \(H(x,y,z)=x^2+y^2+z^2\) H ( x , y , z ) = x 2 + y 2 + z 2 that leaves invariant any sphere centered at the origin, \({\mathbb {S}}_\rho ^2=\{(x,y,z)\in {\mathbb {R}}^3: x^2+y^2+z^2=\rho ^2\}\) S ρ 2 = { ( x , y , z ) R 3 : x 2 + y 2 + z 2 = ρ 2 } . We denote this class by \(\mathcal {X}\) X and by \(\mathcal {X}_n\) X n when \(X^\pm \) X ± are polynomial vector fields of degree n. Our main goal is to study piecewise smooth vector fields in the class \(\mathcal {X}_1\) X 1 presenting three periodic annuli on the invariant sphere \({\mathbb {S}}_1^2\) S 1 2 proving that there exists a mixed simultaneous configuration with at least five limit cycles bifurcating simultaneously of them, considering polynomial perturbations inside the class \(\mathcal {X}_2\) X 2 .