Pub Date : 2025-12-10DOI: 10.1016/j.jde.2025.114031
Lucas Alland , Robert Viator
We consider Steklov eigenvalues of nearly circular domains in of fixed unitary area. In [19], the authors treated such domains as perturbations of the disk, and they computed the first-order term of the asymptotic expansions of the Steklov eigenvalues for reflection-symmetric perturbations; here, we expand these first-order results beyond reflection-symmetry. We also recover the second-order asymptotic expansions, which enable us to prove that no Steklov eigenvalue beyond the first positive one is locally shape-optimized by the disk.
{"title":"Steklov eigenvalues of nearly circular area-normalized domains","authors":"Lucas Alland , Robert Viator","doi":"10.1016/j.jde.2025.114031","DOIUrl":"10.1016/j.jde.2025.114031","url":null,"abstract":"<div><div>We consider Steklov eigenvalues of nearly circular domains in <span><math><msup><mrow><mi>R</mi></mrow><mrow><mn>2</mn></mrow></msup></math></span> of fixed unitary area. In <span><span>[19]</span></span>, the authors treated such domains as perturbations of the disk, and they computed the first-order term of the asymptotic expansions of the Steklov eigenvalues for reflection-symmetric perturbations; here, we expand these first-order results beyond reflection-symmetry. We also recover the second-order asymptotic expansions, which enable us to prove that no Steklov eigenvalue beyond the first positive one is locally shape-optimized by the disk.</div></div>","PeriodicalId":15623,"journal":{"name":"Journal of Differential Equations","volume":"458 ","pages":"Article 114031"},"PeriodicalIF":2.3,"publicationDate":"2025-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145705451","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-10DOI: 10.1016/j.jde.2025.114033
Van Tien Nguyen , Zhi-An Wang , Kaiqiang Zhang
Based on the method of matched asymptotic expansions and Banach fixed point theorem, we rigorously construct infinitely many self-similar blow-up profiles for the parabolic-elliptic Keller-Segel system where . Our findings demonstrate that the infinitely many backward self-similar profiles approximate the rescaling radial steady-state near the origin (i.e. ) and at spatial infinity (i.e. ). We also establish the convergence of the self-similar blow-up solutions as time tends to the blow-up time . Our results can give a refined description of backward self-similar profiles for all rather than for or , indicating that the blow-up point is the origin and
{"title":"Infinitely many self-similar blow-up profiles for the Keller-Segel system in dimensions 3 to 9","authors":"Van Tien Nguyen , Zhi-An Wang , Kaiqiang Zhang","doi":"10.1016/j.jde.2025.114033","DOIUrl":"10.1016/j.jde.2025.114033","url":null,"abstract":"<div><div>Based on the method of matched asymptotic expansions and Banach fixed point theorem, we rigorously construct infinitely many self-similar blow-up profiles for the parabolic-elliptic Keller-Segel system<span><span><span><math><mrow><mo>{</mo><mtable><mtr><mtd><msub><mrow><mo>∂</mo></mrow><mrow><mi>t</mi></mrow></msub><mi>u</mi><mo>=</mo><mi>Δ</mi><mi>u</mi><mo>−</mo><mi>∇</mi><mo>⋅</mo><mrow><mo>(</mo><mi>u</mi><mi>∇</mi><msub><mrow><mi>Φ</mi></mrow><mrow><mi>u</mi></mrow></msub><mo>)</mo></mrow><mo>,</mo></mtd></mtr><mtr><mtd><mn>0</mn><mo>=</mo><mi>Δ</mi><msub><mrow><mi>Φ</mi></mrow><mrow><mi>u</mi></mrow></msub><mo>+</mo><mi>u</mi><mo>,</mo></mtd></mtr><mtr><mtd><mi>u</mi><mo>(</mo><mo>⋅</mo><mo>,</mo><mn>0</mn><mo>)</mo><mo>=</mo><msub><mrow><mi>u</mi></mrow><mrow><mn>0</mn></mrow></msub><mo>≥</mo><mn>0</mn></mtd></mtr></mtable><mspace></mspace><mtext>in</mtext><mspace></mspace><msup><mrow><mi>R</mi></mrow><mrow><mi>d</mi></mrow></msup><mo>,</mo></mrow></math></span></span></span> where <span><math><mi>d</mi><mo>∈</mo><mo>{</mo><mn>3</mn><mo>,</mo><mo>⋯</mo><mo>,</mo><mn>9</mn><mo>}</mo></math></span>. Our findings demonstrate that the infinitely many backward self-similar profiles approximate the rescaling radial steady-state near the origin (i.e. <span><math><mn>0</mn><mo><</mo><mo>|</mo><mi>x</mi><mo>|</mo><mo>≪</mo><mn>1</mn></math></span>) and <span><math><mfrac><mrow><mn>2</mn><mo>(</mo><mi>d</mi><mo>−</mo><mn>2</mn><mo>)</mo></mrow><mrow><mo>|</mo><mi>x</mi><msup><mrow><mo>|</mo></mrow><mrow><mn>2</mn></mrow></msup></mrow></mfrac></math></span> at spatial infinity (i.e. <span><math><mo>|</mo><mi>x</mi><mo>|</mo><mo>≫</mo><mn>1</mn></math></span>). We also establish the convergence of the self-similar blow-up solutions as time tends to the blow-up time <span><math><mi>T</mi><mo>></mo><mn>0</mn></math></span>. Our results can give a refined description of backward self-similar profiles for all <span><math><mo>|</mo><mi>x</mi><mo>|</mo><mo>≥</mo><mn>0</mn></math></span> rather than for <span><math><mn>0</mn><mo><</mo><mo>|</mo><mi>x</mi><mo>|</mo><mo>≪</mo><mn>1</mn></math></span> or <span><math><mo>|</mo><mi>x</mi><mo>|</mo><mo>≫</mo><mn>1</mn></math></span>, indicating that the blow-up point is the origin and<span><span><span><math><mi>u</mi><mo>(</mo><mi>x</mi><mo>,</mo><mi>t</mi><mo>)</mo><mo>∼</mo><mfrac><mrow><mn>1</mn></mrow><mrow><mo>|</mo><mi>x</mi><msup><mrow><mo>|</mo></mrow><mrow><mn>2</mn></mrow></msup></mrow></mfrac><mo>,</mo><mspace></mspace><mspace></mspace><mspace></mspace><mi>x</mi><mo>≠</mo><mn>0</mn><mo>,</mo><mspace></mspace><mtext>as</mtext><mspace></mspace><mi>t</mi><mo>→</mo><mi>T</mi><mo>.</mo></math></span></span></span></div></div>","PeriodicalId":15623,"journal":{"name":"Journal of Differential Equations","volume":"458 ","pages":"Article 114033"},"PeriodicalIF":2.3,"publicationDate":"2025-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145705453","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-10DOI: 10.1016/j.jde.2025.114034
Erwin Luesink , Oliver D. Street
We show how Langevin diffusions can be interpreted in the context of stochastic Hamiltonian systems with structure-preserving noise and dissipation on reductive Lie groups. Reductive Lie groups provide the setting in which the Lie group structure is compatible with Riemannian structures, via the existence of bi-invariant metrics. This structure allows for the explicit construction of Riemannian Brownian motion via symplectic techniques, which permits the study of Langevin diffusions with noise in the position coordinate as well as Langevin diffusions with noise in both momentum and position.
{"title":"Symplectic techniques for stochastic differential equations on reductive Lie groups with applications to Langevin diffusions","authors":"Erwin Luesink , Oliver D. Street","doi":"10.1016/j.jde.2025.114034","DOIUrl":"10.1016/j.jde.2025.114034","url":null,"abstract":"<div><div>We show how Langevin diffusions can be interpreted in the context of stochastic Hamiltonian systems with structure-preserving noise and dissipation on reductive Lie groups. Reductive Lie groups provide the setting in which the Lie group structure is compatible with Riemannian structures, via the existence of bi-invariant metrics. This structure allows for the explicit construction of Riemannian Brownian motion via symplectic techniques, which permits the study of Langevin diffusions with noise in the position coordinate as well as Langevin diffusions with noise in both momentum and position.</div></div>","PeriodicalId":15623,"journal":{"name":"Journal of Differential Equations","volume":"458 ","pages":"Article 114034"},"PeriodicalIF":2.3,"publicationDate":"2025-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145705452","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-09DOI: 10.1016/j.jde.2025.113951
Jakob Nowicki-Koth
In this article, we address the Cauchy problem associated with the k-generalized Zakharov-Kuznetsov equation posed on . By establishing an almost optimal linear -estimate, along with a family of bilinear refinements, we significantly lower the well-posedness threshold for all . In particular, we show that the modified Zakharov-Kuznetsov equation is locally well-posed in for all .
{"title":"Strichartz estimates for the generalized Zakharov-Kuznetsov equation on R×T and applications","authors":"Jakob Nowicki-Koth","doi":"10.1016/j.jde.2025.113951","DOIUrl":"10.1016/j.jde.2025.113951","url":null,"abstract":"<div><div>In this article, we address the Cauchy problem associated with the <em>k</em>-generalized Zakharov-Kuznetsov equation posed on <span><math><mi>R</mi><mo>×</mo><mi>T</mi></math></span>. By establishing an almost optimal linear <span><math><msup><mrow><mi>L</mi></mrow><mrow><mn>4</mn></mrow></msup></math></span>-estimate, along with a family of bilinear refinements, we significantly lower the well-posedness threshold for all <span><math><mi>k</mi><mo>≥</mo><mn>2</mn></math></span>. In particular, we show that the modified Zakharov-Kuznetsov equation is locally well-posed in <span><math><msup><mrow><mi>H</mi></mrow><mrow><mi>s</mi></mrow></msup><mo>(</mo><mi>R</mi><mo>×</mo><mi>T</mi><mo>)</mo></math></span> for all <span><math><mi>s</mi><mo>></mo><mfrac><mrow><mn>11</mn></mrow><mrow><mn>24</mn></mrow></mfrac></math></span>.</div></div>","PeriodicalId":15623,"journal":{"name":"Journal of Differential Equations","volume":"455 ","pages":"Article 113951"},"PeriodicalIF":2.3,"publicationDate":"2025-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145733476","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-09DOI: 10.1016/j.jde.2025.114032
Wanyong Shim
We study the stability of composite waves consisting of a shock profile and a rarefaction wave for the one-dimensional isothermal Navier–Stokes–Poisson (NSP) system, which describes the ion dynamics in a collision-dominated plasma. More precisely, we prove that if the initial data are sufficiently close in the norm to the Riemann data corresponding to a solution consisting of a shock and a rarefaction wave of the associated quasi-neutral Euler system, then the solution to the Cauchy problem for the NSP system converges, up to a dynamical shift, to a superposition of the corresponding shock profile and the rarefaction wave as time tends to infinity. Our proof is based on the method of a-contraction with shifts, which has recently been applied to the Navier–Stokes equations to establish the asymptotic stability of composite waves. To adapt this method to the NSP system, we employ a modulated relative functional introduced in our previous work on the stability of single shock profiles.
{"title":"Asymptotic stability of composite waves of shock profile and rarefaction for the Navier–Stokes–Poisson system","authors":"Wanyong Shim","doi":"10.1016/j.jde.2025.114032","DOIUrl":"10.1016/j.jde.2025.114032","url":null,"abstract":"<div><div>We study the stability of composite waves consisting of a shock profile and a rarefaction wave for the one-dimensional isothermal Navier–Stokes–Poisson (NSP) system, which describes the ion dynamics in a collision-dominated plasma. More precisely, we prove that if the initial data are sufficiently close in the <span><math><msup><mrow><mi>H</mi></mrow><mrow><mn>2</mn></mrow></msup></math></span> norm to the Riemann data corresponding to a solution consisting of a shock and a rarefaction wave of the associated quasi-neutral Euler system, then the solution to the Cauchy problem for the NSP system converges, up to a dynamical shift, to a superposition of the corresponding shock profile and the rarefaction wave as time tends to infinity. Our proof is based on the method of <em>a</em>-contraction with shifts, which has recently been applied to the Navier–Stokes equations to establish the asymptotic stability of composite waves. To adapt this method to the NSP system, we employ a modulated relative functional introduced in our previous work on the stability of single shock profiles.</div></div>","PeriodicalId":15623,"journal":{"name":"Journal of Differential Equations","volume":"458 ","pages":"Article 114032"},"PeriodicalIF":2.3,"publicationDate":"2025-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145705322","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-08DOI: 10.1016/j.jde.2025.114013
Joannis Alexopoulos, Björn de Rijk
Recently, a nonlinear stability theory has been developed for wave trains in reaction-diffusion systems relying on pure -estimates. In the absence of localization of perturbations, it exploits diffusive decay caused by smoothing together with spatio-temporal phase modulation. In this paper, we advance this theory beyond the parabolic setting and propose a scheme designed for general dissipative semilinear problems. We present our method in the context of the FitzHugh-Nagumo system. The lack of parabolicity and localization complicates mode filtration in -spaces using the Floquet-Bloch transform. Instead, we employ the inverse Laplace representation of the semigroup generated by the linearization to uncover high-frequency damping, while leveraging a link to the Floquet-Bloch representation for the smoothing low-frequency part. Another challenge arises in controlling regularity in the quasilinear iteration scheme for the modulated perturbation. We address this by extending the method of nonlinear damping estimates to nonlocalized perturbations using uniformly local Sobolev norms.
{"title":"Nonlinear stability of periodic wave trains in the FitzHugh-Nagumo system against fully nonlocalized perturbations","authors":"Joannis Alexopoulos, Björn de Rijk","doi":"10.1016/j.jde.2025.114013","DOIUrl":"10.1016/j.jde.2025.114013","url":null,"abstract":"<div><div>Recently, a nonlinear stability theory has been developed for wave trains in reaction-diffusion systems relying on pure <span><math><msup><mrow><mi>L</mi></mrow><mrow><mo>∞</mo></mrow></msup></math></span>-estimates. In the absence of localization of perturbations, it exploits diffusive decay caused by smoothing together with spatio-temporal phase modulation. In this paper, we advance this theory beyond the parabolic setting and propose a scheme designed for general dissipative semilinear problems. We present our method in the context of the FitzHugh-Nagumo system. The lack of parabolicity and localization complicates mode filtration in <span><math><msup><mrow><mi>L</mi></mrow><mrow><mo>∞</mo></mrow></msup></math></span>-spaces using the Floquet-Bloch transform. Instead, we employ the inverse Laplace representation of the semigroup generated by the linearization to uncover high-frequency damping, while leveraging a link to the Floquet-Bloch representation for the smoothing low-frequency part. Another challenge arises in controlling regularity in the quasilinear iteration scheme for the modulated perturbation. We address this by extending the method of nonlinear damping estimates to nonlocalized perturbations using uniformly local Sobolev norms.</div></div>","PeriodicalId":15623,"journal":{"name":"Journal of Differential Equations","volume":"457 ","pages":"Article 114013"},"PeriodicalIF":2.3,"publicationDate":"2025-12-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145749281","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-08DOI: 10.1016/j.jde.2025.113939
Anuj Kumar , Vincent R. Martinez
This paper considers a family of active scalar equations which modify the generalized surface quasi-geostrophic (gSQG) equations through its constitutive law and a dissipative perturbation. These modifications are characteristically mild in the sense that they are logarithmic. The problem of well posedness, in the sense of Hadamard, is then studied in a borderline setting of regularity in analogy to the scaling-critical spaces of the gSQG equations. A novelty of the system considered is the nuanced form of smoothing provided by the proposed mild form of dissipation, which is able to support global well-posedness at the Euler endpoint, but in a setting where the inviscid counterpart is known to be ill-posed. A novelty of the analysis lies in the simultaneous treatment of modifications in the constitutive law, dissipative mechanism, and functional setting, which the existing literature has typically treated separately. A putatively sharp relation is identified between each of the distinct system-modifiers that is consistent with previous studies that considered these modifications in isolation. This unified perspective is afforded by the introduction of a linear model equation, referred to as the protean system, that successfully incorporates the more delicate commutator structure collectively possessed by the gSQG family and upon which each facet of well-posedness can effectively be reduced to its study.
{"title":"On well-posedness of a mildly dissipative family of active scalar equations in borderline Sobolev spaces","authors":"Anuj Kumar , Vincent R. Martinez","doi":"10.1016/j.jde.2025.113939","DOIUrl":"10.1016/j.jde.2025.113939","url":null,"abstract":"<div><div>This paper considers a family of active scalar equations which modify the generalized surface quasi-geostrophic (gSQG) equations through its constitutive law and a dissipative perturbation. These modifications are characteristically mild in the sense that they are logarithmic. The problem of well posedness, in the sense of Hadamard, is then studied in a borderline setting of regularity in analogy to the scaling-critical spaces of the gSQG equations. A novelty of the system considered is the nuanced form of smoothing provided by the proposed mild form of dissipation, which is able to support global well-posedness at the Euler endpoint, but in a setting where the inviscid counterpart is known to be ill-posed. A novelty of the analysis lies in the simultaneous treatment of modifications in the constitutive law, dissipative mechanism, and functional setting, which the existing literature has typically treated separately. A putatively sharp relation is identified between each of the distinct system-modifiers that is consistent with previous studies that considered these modifications in isolation. This unified perspective is afforded by the introduction of a linear model equation, referred to as the <em>protean system</em>, that successfully incorporates the more delicate commutator structure collectively possessed by the gSQG family and upon which each facet of well-posedness can effectively be reduced to its study.</div></div>","PeriodicalId":15623,"journal":{"name":"Journal of Differential Equations","volume":"457 ","pages":"Article 113939"},"PeriodicalIF":2.3,"publicationDate":"2025-12-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145749280","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-05DOI: 10.1016/j.jde.2025.113866
Maximilian Engel , Guillermo Olicón-Méndez
In this work we study the Brusselator – a prototypical model for chemical oscillations– under the assumption that the bifurcation parameter is of order for positive . The dynamics of this mathematical model exhibits a time scale separation visible via fast and slow regimes along its unique attracting limit cycle. This limit cycle accumulates at infinity as , so that appropriate coordinates are used to analyse the dynamics near the line at infinity, corresponding to the set . This object becomes a nonhyperbolic invariant manifold for which we use a desingularising rescaling, in order to study the closeby dynamics. Further use of geometric singular perturbation techniques allows us to give a decomposition of the Brusselator limit cycle in terms of four different fully quantified time scales for small ϵ.
{"title":"A singular perturbation analysis for the Brusselator","authors":"Maximilian Engel , Guillermo Olicón-Méndez","doi":"10.1016/j.jde.2025.113866","DOIUrl":"10.1016/j.jde.2025.113866","url":null,"abstract":"<div><div>In this work we study the Brusselator – a prototypical model for chemical oscillations– under the assumption that the bifurcation parameter is of order <span><math><mi>O</mi><mo>(</mo><mn>1</mn><mo>/</mo><mi>ϵ</mi><mo>)</mo></math></span> for positive <span><math><mi>ϵ</mi><mo>≪</mo><mn>1</mn></math></span>. The dynamics of this mathematical model exhibits a time scale separation visible via fast and slow regimes along its unique attracting limit cycle. This limit cycle accumulates at infinity as <span><math><mi>ϵ</mi><mo>→</mo><mn>0</mn></math></span>, so that appropriate coordinates <span><math><mo>(</mo><mi>w</mi><mo>,</mo><mi>z</mi><mo>)</mo></math></span> are used to analyse the dynamics near the <em>line at infinity</em>, corresponding to the set <span><math><mo>{</mo><mi>z</mi><mo>=</mo><mn>0</mn><mo>}</mo></math></span>. This object becomes a nonhyperbolic invariant manifold for which we use a desingularising rescaling, in order to study the closeby dynamics. Further use of geometric singular perturbation techniques allows us to give a decomposition of the Brusselator limit cycle in terms of four different fully quantified time scales for small <em>ϵ</em>.</div></div>","PeriodicalId":15623,"journal":{"name":"Journal of Differential Equations","volume":"457 ","pages":"Article 113866"},"PeriodicalIF":2.3,"publicationDate":"2025-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145693189","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-05DOI: 10.1016/j.jde.2025.114006
Magnus Perninge
We prove the existence and uniqueness of viscosity solutions to quasi-variational inequalities (QVIs) with both upper and lower obstacles. In contrast to most previous works, we allow all involved coefficients to depend on the state variable and do not assume any type of monotonicity. It is well known that double obstacle QVIs are related to zero-sum games of impulse control, and our existence result is derived by considering a sequence of such games. Full generality is obtained by allowing one player in the game to randomize their control. A by-product of our result is that the corresponding zero-sum game has a value.
Utilizing recent results for backward stochastic differential equations (BSDEs), we find that the unique viscosity solution to our QVI is related to optimal stopping of BSDEs with constrained jumps and, in particular, to the corresponding non-linear Snell envelope. This gives a new probabilistic representation for double obstacle QVIs.
{"title":"Probabilistic representation for viscosity solutions to double-obstacle quasi-variational inequalities","authors":"Magnus Perninge","doi":"10.1016/j.jde.2025.114006","DOIUrl":"10.1016/j.jde.2025.114006","url":null,"abstract":"<div><div>We prove the existence and uniqueness of viscosity solutions to quasi-variational inequalities (QVIs) with both upper and lower obstacles. In contrast to most previous works, we allow all involved coefficients to depend on the state variable and do not assume any type of monotonicity. It is well known that double obstacle QVIs are related to zero-sum games of impulse control, and our existence result is derived by considering a sequence of such games. Full generality is obtained by allowing one player in the game to randomize their control. A by-product of our result is that the corresponding zero-sum game has a value.</div><div>Utilizing recent results for backward stochastic differential equations (BSDEs), we find that the unique viscosity solution to our QVI is related to optimal stopping of BSDEs with constrained jumps and, in particular, to the corresponding non-linear Snell envelope. This gives a new probabilistic representation for double obstacle QVIs.</div></div>","PeriodicalId":15623,"journal":{"name":"Journal of Differential Equations","volume":"456 ","pages":"Article 114006"},"PeriodicalIF":2.3,"publicationDate":"2025-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145681044","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-05DOI: 10.1016/j.jde.2025.114030
Rama Rawat, Haripada Roy, Prosenjit Roy
The aim of this work is to establish some cases of the Caffarelli-Kohn-Nirenberg inequalities on the Heisenberg group for fractional Sobolev spaces. Here, we work with the fractional Sobolev spaces introduced by Adimurthi and Mallick (2018) [1], which provide a general framework in the context of the Heisenberg group. Our inequalities, in particular, contain the fractional Hardy's inequality and Sobolev inequality established by them, and also extend the admissible range of indices for the fractional Hardy's inequality.
{"title":"Fractional Caffarelli-Kohn-Nirenberg type inequalities on the Heisenberg group","authors":"Rama Rawat, Haripada Roy, Prosenjit Roy","doi":"10.1016/j.jde.2025.114030","DOIUrl":"10.1016/j.jde.2025.114030","url":null,"abstract":"<div><div>The aim of this work is to establish some cases of the Caffarelli-Kohn-Nirenberg inequalities on the Heisenberg group for fractional Sobolev spaces. Here, we work with the fractional Sobolev spaces introduced by Adimurthi and Mallick (2018) <span><span>[1]</span></span>, which provide a general framework in the context of the Heisenberg group. Our inequalities, in particular, contain the fractional Hardy's inequality and Sobolev inequality established by them, and also extend the admissible range of indices for the fractional Hardy's inequality.</div></div>","PeriodicalId":15623,"journal":{"name":"Journal of Differential Equations","volume":"457 ","pages":"Article 114030"},"PeriodicalIF":2.3,"publicationDate":"2025-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145693188","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}