{"title":"IMEX variable step-size Runge-Kutta methods for parabolic integro-differential equations with nonsmooth initial data","authors":"Wansheng Wang, Mengli Mao, Zifeng Li","doi":"10.4310/cms.2024.v22.n6.a6","DOIUrl":"https://doi.org/10.4310/cms.2024.v22.n6.a6","url":null,"abstract":"We develop a class of implicit-explicit (IMEX) Runge-Kutta (RK) methods for solving parabolic integro-differential equations (PIDEs) with nonsmooth initial data, which describe several option pricing models in mathematical finance. Different from the usual IMEX RK methods, the proposed methods approximate the integral term explicitly by using an extrapolation operator based on the stage-values of RK methods, and we call them as IMEX stage-based interpolation RK (SBIRK) methods. It is shown that there exist arbitrarily high order IMEX SBIRK methods which are stable for abstract PIDEs under suitable time step restrictions. The consistency error and the global error bounds for this class of IMEX Runge-Kutta methods are derived for abstract PIDEs with nonsmooth initial data. The related higher time regularity analysis of the exact solution and stability estimates for IMEX SBIRK methods play key roles in deriving these error bounds. Numerical experiments for European options under jump-diffusion models and stochastic volatility model with jump verify and complement our theoretical results.","PeriodicalId":50659,"journal":{"name":"Communications in Mathematical Sciences","volume":"130 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2024-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141744416","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"A note on the relaxation process in a class of non-equilibrium two-phase flow models","authors":"Jean-Marc Hérard","doi":"10.4310/cms.2024.v22.n6.a2","DOIUrl":"https://doi.org/10.4310/cms.2024.v22.n6.a2","url":null,"abstract":"We focus here on the relaxation process in a class of two-phase flow models, considering first gas-liquid flows, and then liquid-vapour mixtures. The whole analysis enables to exhibit a few conditions on the flow in order to guarantee the time decay of some variables. The former may depend on initial conditions but also on equations of state within each phase. The present analysis aims at providing some better understanding of inner processes, and it is also useful for numerical purposes, as emphasized in appendix B. It is a sequel of paper [J.M. Hérard and G. Jomée, ESAIM Proc. Surv., 72:19–40, 2023] where the sole pressure relaxation process in some multiphase flow models is investigated.","PeriodicalId":50659,"journal":{"name":"Communications in Mathematical Sciences","volume":"31 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2024-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141744413","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"The hydrostatic limit of the Beris-Edwards system in dimension two","authors":"Xingyu Li, Marius Paicu, Arghir Zarnescu","doi":"10.4310/cms.2024.v22.n6.a11","DOIUrl":"https://doi.org/10.4310/cms.2024.v22.n6.a11","url":null,"abstract":"We study the scaled anisotropic co-rotational Beris-Edwards system modeling the hydrodynamic motion of nematic liquid crystals in dimension two. We prove the global well-posedness with small analytic data in a thin strip domain. Moreover, we justify the limit to a system involving the hydrostatic Navier-Stokes system with analytic data and prove the convergence.","PeriodicalId":50659,"journal":{"name":"Communications in Mathematical Sciences","volume":"28 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2024-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141744421","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Existence and large time behavior for a dissipative variant of the rotational NLS equation","authors":"Paolo Antonelli, Boris Shakarov","doi":"10.4310/cms.2024.v22.n6.a7","DOIUrl":"https://doi.org/10.4310/cms.2024.v22.n6.a7","url":null,"abstract":"We study a dissipative variant of the Gross-Pitaevskii equation with rotation. The model contains a nonlocal, nonlinear term that forces the conservation of $L^2$-norm of solutions. We are motivated by several physical experiments and numerical simulations studying the formation of vortices in Bose-Einstein condensates.We show local and global well-posedness of this model and investigate the asymptotic behavior of its solutions. In the linear case, the solution asymptotically tends to the eigenspace associated with the smallest eigenvalue in the decomposition of the initial datum. In the nonlinear case, we obtain weak convergence to a stationary state. Moreover, for initial energies in a specific range, we prove strong asymptotic stability of ground state solutions.","PeriodicalId":50659,"journal":{"name":"Communications in Mathematical Sciences","volume":"22 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2024-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141746475","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"An efficient interface hydrostatic reconstruction for the two-layer shallow flows with arbitrary wet-dry fronts","authors":"Jian Dong, Dingfang Li","doi":"10.4310/cms.2024.v22.n6.a9","DOIUrl":"https://doi.org/10.4310/cms.2024.v22.n6.a9","url":null,"abstract":"This paper aims to propose a well-balanced positivity-preserving numerical scheme for the two-layer shallow water systems with arbitrary wet-dry fronts based on interface hydrostatic reconstructions (IHR). One key difficulty in solving the two-layer shallow water systems is the nonconservative product term which cannot be evaluated on the cell boundaries. Another difficulty is that the well-balanced property for the still water maybe missed when the computational domain has wet-dry fronts, especially, the wet-dry front is located at the discontinuous bottom topography. For the nonlinear stability of the numerical scheme, the positivity of the water height is vital. To this end, we discretize the nonconservative product term based on the IHR method, which is a particular choice of path-conservative methods. The intermediate bottom level used in the discretization of the bed source term of two layers is different. The nonconservative product term due to the momentum exchange between two layers is discretized using the intermediate interface water height. The resulting numerical scheme can preserve the positivity of two-layered heights and maintain the still water even when the computational domain has wet-dry fronts. The numerical scheme performs well in solving the complex problems, such as the Kelvin-Helmholtz instable problems. We demonstrate these properties of the current scheme through several classical problems of the two-layer shallow water systems with arbitrary wet-dry fronts.","PeriodicalId":50659,"journal":{"name":"Communications in Mathematical Sciences","volume":"15 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2024-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141744419","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"A note on enhanced dissipation of time-dependent shear flows","authors":"Daniel Coble, Siming He","doi":"10.4310/cms.2024.v22.n6.a10","DOIUrl":"https://doi.org/10.4310/cms.2024.v22.n6.a10","url":null,"abstract":"This paper explores the phenomena of enhanced dissipation in solutions to the passive scalar equations subject to time-dependent shear flows. The hypocoercivity functionals with carefully tuned time weights are applied in the analysis. We observe that as long as the critical points of the shear flow vary slowly, one can derive the sharp enhanced dissipation estimates, mirroring the ones obtained for the time-stationary case.","PeriodicalId":50659,"journal":{"name":"Communications in Mathematical Sciences","volume":"13 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2024-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141744418","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Maxime Bouchereau, Philippe Chartier, Mohammed Lemou, Florian Méhats
{"title":"Machine learning methods for autonomous ordinary differential equations","authors":"Maxime Bouchereau, Philippe Chartier, Mohammed Lemou, Florian Méhats","doi":"10.4310/cms.2024.v22.n6.a1","DOIUrl":"https://doi.org/10.4310/cms.2024.v22.n6.a1","url":null,"abstract":"Ordinary Differential Equations are generally too complex to be solved analytically. Approximations thereof can be obtained by general purpose numerical methods. However, even though accurate schemes have been developed, they remain computationally expensive: In this paper, we resort to the theory of modified equations in order to obtain “on the fly” cheap numerical approximations. The recipe consists in approximating, prior to that, the modified field associated to the modified equation by <i>neural networks</i>. Elementary convergence results are then established and the efficiency of the technique is demonstrated on experiments.","PeriodicalId":50659,"journal":{"name":"Communications in Mathematical Sciences","volume":"7 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2024-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141744411","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Global smooth solutions to the two-dimensional axisymmetric Zeldovich-von Neumann-Döring combustion equations with swirl","authors":"Honghua Chen, Geng Lai, Wancheng Sheng","doi":"10.4310/cms.2024.v22.n6.a5","DOIUrl":"https://doi.org/10.4310/cms.2024.v22.n6.a5","url":null,"abstract":"This paper studies the two-dimensional (2D) Zeldovich-von Neumann-Döring (ZND) combustion equations with initial data, which are a combination of an axisymmetric flow in a ring and vacuum in the remaining domain. Existence of a global-in-time smooth solution to the initial value problem is obtained by the method of characteristic decomposition, provided that the initial data satisfy some sufficient conditions. The large-time behavior of the solution is also studied. As a result, at any time, the ring continues to expand until the gas burns out in infinite time for the system. The solution describes a phenomenon of the expansion of 2D reacting flows with swirl in vacuum or a phenomenon of “fire whirl”.","PeriodicalId":50659,"journal":{"name":"Communications in Mathematical Sciences","volume":"21 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2024-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141744414","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Localization and the landscape function for regular Sturm-Liouville operators","authors":"Mirza Karamehmedović, Faouzi Triki","doi":"10.4310/cms.2024.v22.n6.a12","DOIUrl":"https://doi.org/10.4310/cms.2024.v22.n6.a12","url":null,"abstract":"We consider the localization in the eigenfunctions of regular Sturm-Liouville operators. After deriving non-asymptotic and asymptotic lower and upper bounds on the localization coefficient of the eigenfunctions, we characterize the landscape function in terms of the first eigenfunction. Several numerical experiments are provided to illustrate the obtained theoretical results.","PeriodicalId":50659,"journal":{"name":"Communications in Mathematical Sciences","volume":"64 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2024-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141744422","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"The gravitational Vlasov-Poisson system with infinite mass and velocities in $mathbb{R}^3$","authors":"Guido Cavallaro, Carlo Marchioro","doi":"10.4310/cms.2024.v22.n5.a11","DOIUrl":"https://doi.org/10.4310/cms.2024.v22.n5.a11","url":null,"abstract":"We study existence and uniqueness of the solution to the gravitational Vlasov–Poisson system evolving in $mathbb{R}^3$. It is assumed that initially the particles are distributed according to a spatial density with a power-law decay in space, allowing for unbounded mass, and an exponential decay in velocities given by a Maxwell–Boltzmann law. We extend a classical result which holds for systems with finite total mass.","PeriodicalId":50659,"journal":{"name":"Communications in Mathematical Sciences","volume":"46 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2024-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141719564","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}