Open research questions in Nonlinear Partial Differential Equations
88 unresolved questions extracted from the limitations and future-work sections of 831 Nonlinear Partial Differential Equations papers in our library. Each links back to the study that raised it.
What the literature leaves open
Future research could focus on extending the results of the paper to more general domains and potentials. Future research could also focus on applying the methods of the paper to other non-local equations.
The paper identifies a gap in the prior literature on the study of multi-peak solutions for the fractional Schrödinger equation. The paper aims to fill this gap by establishing the existence of multi-peak solutions.
The paper identifies a gap in the existing literature by considering the case with non-convex constitutive stress relations and non-degenerate Lax’s shock. The paper also addresses the lack of results for large-amplitude shocks and space-periodic perturbations.
Stability of large-amplitude viscous shock under periodic perturbation for 1-d viscoelasticity with non-convex constitutive relations · 2026 · DOIThe paper assumes certain conditions on the parameters μ, κ, and q. The analysis is limited to the case of a ground state normalized solution. The authors do not provide numerical simulations or experimental results.
Multiple Normalized Solutions for the Quasilinear Sobolev Critical Schrödinger-Poisson System · 2026 · DOIFuture research could focus on numerical simulations and experimental results. The study of related systems and phenomena could benefit from the paper's findings. Further analysis of the quasilinear Sobolev critical Schrödinger-Poisson system could lead to new insights.
Multiple Normalized Solutions for the Quasilinear Sobolev Critical Schrödinger-Poisson System · 2026 · DOIThe Grushin operator is degenerate on the subspace {0} × Rn. The paper needs to establish the Palais-Smale compactness condition for the functional Jγ.
The presence of sign-changing prescribed functions makes the mean field equation challenging to solve. The lack of sufficient conditions for the existence of solutions in critical cases is a significant challenge.
Critical mean field equations for equilibrium turbulence with sign-changing prescribed functions · 2026 · DOIThe 1-Laplacian operator introduces analytical challenges due to its degenerate and non-smooth nature. The lack of compactness is a challenge that is overcome using the Vitali Convergence Theorem.
Quasicritical elliptic equation involving 1-Laplacian operator with Robin and Neumann Boundary conditions · 2026 · DOIThe nonlocal nature of the Hamilton-Jacobi equations. The need for a generalized notion of Mather measure. The challenge of characterizing the constant c.
The paper identifies a gap in the existing literature regarding boundary pointwise regularity results for weak solutions to the Poisson problem on uniform domains. The authors seek to address this gap using a novel definition of weak solutions and compactness methods.
There is a gap in the existing literature regarding higher regularity properties of solutions to fully nonlinear elliptic equations. The existing literature does not provide a complete understanding of the regularity properties of solutions to fully nonlinear elliptic equations.
The paper suggests that future research could focus on extending the estimates to more general classes of equations. The paper notes that the estimates could be used to study the regularity properties of solutions of quasilinear elliptic equations in divergence form with rapidly oscillating periodic coefficients. The paper suggests that the estimates could be applied to various applications, including homogenization of p-Laplace type equations.
Regularity for monotone operators and applications to homogenization of p-Laplace type equations · 2026 · DOIThe paper identifies a gap in the existing literature, where estimates are typically derived under strong monotonicity conditions. The paper notes that a weaker condition is needed to obtain Calderon-Zygmund type estimates for quasilinear elliptic equations in divergence form with rapidly oscillating periodic coefficients.
Regularity for monotone operators and applications to homogenization of p-Laplace type equations · 2026 · DOITo study the behavior of solutions to nonlinear elliptic equations on the hyperbolic space. To generalize the result to other types of equations or spaces.
Conformally invariant equations with negative critical exponents on the three dimensional hyperbolic space · 2026 · DOIThe lack of symmetry results for positive entire solutions to fourth-order equations on the hyperbolic space. The need to generalize previous results on the Euclidean space to the hyperbolic space.
Conformally invariant equations with negative critical exponents on the three dimensional hyperbolic space · 2026 · DOIThe gap involves analyzing regularly varying functions at zero and infinity. The paper aims to establish the existence of positive solutions.
The results are limited to interior critical points. The estimates are limited to fully nonlinear elliptic equations.
The Concentration-Compactness Principle has not been established for Musielak-Orlicz spaces - The existence of weak solutions to quasilinear equations with critical nonlinear terms is not well understood
There is a lack of analysis for the truncated Laplacian in punctured balls. The literature lacks a characterization of the solutions in terms of their asymptotic behavior near the origin.
The lack of compactness in R 3 and the presence of competing nonlinear terms require a refined concentration-compactness analysis. The presence of the variable mass term and mixed nonlinearities requires a more delicate analysis.
Normalized Solutions and Numerical Approximation for a Critical p-Laplacian Schrödinger–Bopp–Podolsky System with Variable Mass and Logarithmic Nonlinearity · 2026 · DOIThe paper identifies a gap in the existing literature on anisotropic equations. The problem of establishing existence results for weak and entropy solutions is addressed.
Regularity of weak and entropy solution for a $$p_i(x)-$$elliptic problems with lower order terms · 2026 · DOIFuture research could consider problems with supercritical growth. The paper provides a new tool for analyzing regularity in partial differential equations, which could be applied to other problems.
Global boundedness for generalized Schrödinger-type double phase problems in $${{\mathbb {R}}}^N$$ and applications to supercritical double phase problems · 2026 · DOIThere is a gap in the literature regarding global boundedness results for weak solutions to generalized Schrödinger-type double phase problems. The paper fills this gap by establishing global boundedness results.
Global boundedness for generalized Schrödinger-type double phase problems in $${{\mathbb {R}}}^N$$ and applications to supercritical double phase problems · 2026 · DOIFuture research should focus on extending the results of the paper to more general domains. Future research should focus on studying the critical points of solutions of elliptic equations in non-simply-connected domains with non-smooth boundaries.
Critical Points of Solutions of Elliptic Equations in Divergence Form in Planar Non-simply-connected Domains with Smooth or Nonsmooth Boundary · 2026 · DOIThe existing literature on the critical points of solutions of elliptic equations is limited to simply connected domains. There is a need for a comprehensive study of the critical points of solutions of elliptic equations in non-simply-connected domains.
Critical Points of Solutions of Elliptic Equations in Divergence Form in Planar Non-simply-connected Domains with Smooth or Nonsmooth Boundary · 2026 · DOI
Most-cited papers in Nonlinear Partial Differential Equations
- Basic results of fractional Orlicz-Sobolev space and applications to non-local problems · Topological Methods in Nonlinear Analysis · 2020 · 16 citations
- THE DIRICHLET PROBLEM FOR A CLASS OF ANISOTROPIC SCHRÖDINGER-KIRCHHOFF-TYPE EQUATIONS WITH CRITICAL EXPONENT · Mathematical Modelling and Analysis · 2024 · 11 citations
- Nonstandard Dirichlet problems with competing (p,q)-Laplacian, convection, and convolution · Studia Universitatis Babes-Bolyai Matematica · 2021 · 10 citations
- Multiplicity of positive solutions for a class of nonlocal problem involving critical exponent · Electronic journal of qualitative theory of differential equations · 2021 · 10 citations
- Separating solutions of nonlinear problems using nonlinear generalized Rayleigh quotients · Topological Methods in Nonlinear Analysis · 2021 · 9 citations
- Asymptotical multiplicity and some reversed variational inequalities · Topological Methods in Nonlinear Analysis · 2002 · 9 citations
- EXISTENCE RESULTS FOR FRACTIONAL P-LAPLACIAN SYSTEMS VIA YOUNG MEASURES · Mathematical Modelling and Analysis · 2022 · 9 citations
- REGULARIZING EFFECT IN SINGULAR SEMILINEAR PROBLEMS · Mathematical Modelling and Analysis · 2023 · 8 citations
- Multiple and particular solutions of a second order discrete boundary value problem with mixed periodic boundary conditions · Electronic journal of qualitative theory of differential equations · 2020 · 8 citations
- Weighted fourth order equation of Kirchhoff type in dimension 4 with non-linear exponential growth · Topological Methods in Nonlinear Analysis · 2023 · 7 citations
Most recent work
- Normalized Solutions and Numerical Approximation for a Critical p-Laplacian Schrödinger–Bopp–Podolsky System with Variable Mass and Logarithmic Nonlinearity · International Journal of Theoretical Physics · 2026
- Construction of bubbling solutions for critical biharmonic problems with critical or non-critical perturbation · Communications in Contemporary Mathematics · 2026
- Li-Yau inequality and Liouville property to a semilinear heat equation on Riemannian manifolds · manuscripta mathematica · 2026
- Normalized solutions for a nonlinear fractional elliptic problem with potentials · Applied Mathematics Letters · 2026
- Nonexistence and boundary behavior of solutions to the <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si11.svg" display="inline" id="d1e48"> <mml:mi>k</mml:mi> </mml:math> -Hessian equation with nonlinear gradient terms · Applied Mathematics Letters · 2026
- A Dirichlet Problem with Degenerate Coercivity · Mediterranean Journal of Mathematics · 2026
- Normalized Solutions for a Schrödinger Equation with Competing Type van der Waals Type Potentials: Existence, Limiting Behavior and Multiplicity · Mediterranean Journal of Mathematics · 2026
- Critical Fractional Problems with Weights: Existence, Minimization, and Pohozaev Obstructions · Mathematics · 2026
- Concentration Phenomena of Normalized Solutions to the Critical Fractional Relativistic Schrödinger Equation with Competing Potentials · Applied Mathematics & Optimization · 2026
- Sharp Estimates for Bubbling Solutions of an Even-Order Mean Field Equation · Communications in Contemporary Mathematics · 2026
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