Conservation Laws and Symmetry Reductions of the Hunter–Saxton Equation via the Double Reduction Method

This study investigates via Lie symmetry analysis the Hunter–Saxton equation, an equation relevant to the theoretical analysis of nematic liquid crystals. We employ the multiplier method to obtain conservation laws of the equation that arise from first-order multipliers. Conservation laws of the equ...

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Main Authors: Molahlehi Charles Kakuli, Winter Sinkala, Phetogo Masemola
Format: Article
Language:English
Published: MDPI AG 2023-08-01
Series:Mathematical and Computational Applications
Subjects:
Online Access:https://www.mdpi.com/2297-8747/28/5/92
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author Molahlehi Charles Kakuli
Winter Sinkala
Phetogo Masemola
author_facet Molahlehi Charles Kakuli
Winter Sinkala
Phetogo Masemola
author_sort Molahlehi Charles Kakuli
collection DOAJ
description This study investigates via Lie symmetry analysis the Hunter–Saxton equation, an equation relevant to the theoretical analysis of nematic liquid crystals. We employ the multiplier method to obtain conservation laws of the equation that arise from first-order multipliers. Conservation laws of the equation, combined with the admitted Lie point symmetries, enable us to perform symmetry reductions by employing the double reduction method. The method exploits the relationship between symmetries and conservation laws to reduce both the number of variables and the order of the equation. Five nontrivial conservation laws of the Hunter–Saxton equation are derived, four of which are found to have associated Lie point symmetries. Applying the double reduction method to the equation results in a set of first-order ordinary differential equations, the solutions of which represent invariant solutions for the equation. While the double reduction method may be more complex to implement than the classical method, since it involves finding Lie point symmetries and deriving conservation laws, it has some advantages over the classical method of reducing PDEs. Firstly, it is more efficient in that it can reduce the number of variables and order of the equation in a single step. Secondly, by incorporating conservation laws, physically meaningful solutions that satisfy important physical constraints can be obtained.
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spelling doaj.art-4567141d26da455daa8d7d86d7838cc32023-11-19T17:15:35ZengMDPI AGMathematical and Computational Applications1300-686X2297-87472023-08-012859210.3390/mca28050092Conservation Laws and Symmetry Reductions of the Hunter–Saxton Equation via the Double Reduction MethodMolahlehi Charles Kakuli0Winter Sinkala1Phetogo Masemola2Department of Mathematical Sciences and Computing, Faculty of Natural Sciences, Walter Sisulu University, Private Bag X1, Mthatha 5117, South AfricaDepartment of Mathematical Sciences and Computing, Faculty of Natural Sciences, Walter Sisulu University, Private Bag X1, Mthatha 5117, South AfricaSchool of Mathematics, University of the Witwatersrand, Johannesburg 2000, South AfricaThis study investigates via Lie symmetry analysis the Hunter–Saxton equation, an equation relevant to the theoretical analysis of nematic liquid crystals. We employ the multiplier method to obtain conservation laws of the equation that arise from first-order multipliers. Conservation laws of the equation, combined with the admitted Lie point symmetries, enable us to perform symmetry reductions by employing the double reduction method. The method exploits the relationship between symmetries and conservation laws to reduce both the number of variables and the order of the equation. Five nontrivial conservation laws of the Hunter–Saxton equation are derived, four of which are found to have associated Lie point symmetries. Applying the double reduction method to the equation results in a set of first-order ordinary differential equations, the solutions of which represent invariant solutions for the equation. While the double reduction method may be more complex to implement than the classical method, since it involves finding Lie point symmetries and deriving conservation laws, it has some advantages over the classical method of reducing PDEs. Firstly, it is more efficient in that it can reduce the number of variables and order of the equation in a single step. Secondly, by incorporating conservation laws, physically meaningful solutions that satisfy important physical constraints can be obtained.https://www.mdpi.com/2297-8747/28/5/92double reductionHunter–Saxton equationlie symmetry analysisconservation lawinvariant solution
spellingShingle Molahlehi Charles Kakuli
Winter Sinkala
Phetogo Masemola
Conservation Laws and Symmetry Reductions of the Hunter–Saxton Equation via the Double Reduction Method
Mathematical and Computational Applications
double reduction
Hunter–Saxton equation
lie symmetry analysis
conservation law
invariant solution
title Conservation Laws and Symmetry Reductions of the Hunter–Saxton Equation via the Double Reduction Method
title_full Conservation Laws and Symmetry Reductions of the Hunter–Saxton Equation via the Double Reduction Method
title_fullStr Conservation Laws and Symmetry Reductions of the Hunter–Saxton Equation via the Double Reduction Method
title_full_unstemmed Conservation Laws and Symmetry Reductions of the Hunter–Saxton Equation via the Double Reduction Method
title_short Conservation Laws and Symmetry Reductions of the Hunter–Saxton Equation via the Double Reduction Method
title_sort conservation laws and symmetry reductions of the hunter saxton equation via the double reduction method
topic double reduction
Hunter–Saxton equation
lie symmetry analysis
conservation law
invariant solution
url https://www.mdpi.com/2297-8747/28/5/92
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AT phetogomasemola conservationlawsandsymmetryreductionsofthehuntersaxtonequationviathedoublereductionmethod