Extended Symmetry of Higher Painlevé Equations of Even Periodicity and Their Rational Solutions
The structure of the extended affine Weyl symmetry group of higher Painlevé equations of <i>N</i> periodicity depends on whether <i>N</i> is even or odd. We find that for even <i>N</i>, the symmetry group <inline-formula><math xmlns="http://www.w3.or...
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Main Authors: | , , , |
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Format: | Article |
Language: | English |
Published: |
MDPI AG
2024-11-01
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Series: | Mathematics |
Subjects: | |
Online Access: | https://www.mdpi.com/2227-7390/12/23/3701 |
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Summary: | The structure of the extended affine Weyl symmetry group of higher Painlevé equations of <i>N</i> periodicity depends on whether <i>N</i> is even or odd. We find that for even <i>N</i>, the symmetry group <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msubsup><mrow><mover accent="true"><mi>A</mi><mo>^</mo></mover></mrow><mrow><mi>N</mi><mo>−</mo><mn>1</mn></mrow><mrow><mo>(</mo><mn>1</mn><mo>)</mo></mrow></msubsup></semantics></math></inline-formula> contains the conventional Bäcklund transformations <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>s</mi><mi>j</mi></msub><mo>,</mo><mi>j</mi><mo>=</mo><mn>1</mn><mo>,</mo><mo>…</mo><mo>,</mo><mi>N</mi></mrow></semantics></math></inline-formula>, the group of automorphisms consisting of cycling permutations but also reflections on a periodic circle of <i>N</i> points, which is a novel feature uncovered in this paper. The presence of reflection automorphisms is connected to the existence of degenerated solutions, and for <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>N</mi><mo>=</mo><mn>4</mn></mrow></semantics></math></inline-formula>, we explicitly show how even reflection automorphisms cause degeneracy of a class of rational solutions obtained on the orbit of the translation operators of <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msubsup><mrow><mover accent="true"><mi>A</mi><mo>^</mo></mover></mrow><mn>3</mn><mrow><mo>(</mo><mn>1</mn><mo>)</mo></mrow></msubsup></semantics></math></inline-formula>. We obtain the closed expressions for the solutions and their degenerated counterparts in terms of the determinants of the Kummer polynomials. |
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ISSN: | 2227-7390 |