@article{MeraTarchanov2017, author = {Mera, Azal Jaafar Musa and Tarchanov, Nikolaj Nikolaevič}, title = {The Neumann Problem after Spencer}, series = {Žurnal Sibirskogo Federalʹnogo Universiteta = Journal of Siberian Federal University : Matematika i fizika = Mathematics \& physics}, volume = {10}, journal = {Žurnal Sibirskogo Federalʹnogo Universiteta = Journal of Siberian Federal University : Matematika i fizika = Mathematics \& physics}, publisher = {Sibirskij Federalʹnyj Universitet}, address = {Krasnojarsk}, issn = {1997-1397}, doi = {10.17516/1997-1397-2017-10-4-474-493}, pages = {474 -- 493}, year = {2017}, abstract = {When trying to extend the Hodge theory for elliptic complexes on compact closed manifolds to the case of compact manifolds with boundary one is led to a boundary value problem for the Laplacian of the complex which is usually referred to as Neumann problem. We study the Neumann problem for a larger class of sequences of differential operators on a compact manifold with boundary. These are sequences of small curvature, i.e., bearing the property that the composition of any two neighbouring operators has order less than two.}, language = {en} } @phdthesis{Mera2017, author = {Mera, Azal Jaafar Musa}, title = {The Navier-Stokes equations for elliptic quasicomplexes}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-398495}, school = {Universit{\"a}t Potsdam}, pages = {101}, year = {2017}, abstract = {The classical Navier-Stokes equations of hydrodynamics are usually written in terms of vector analysis. More promising is the formulation of these equations in the language of differential forms of degree one. In this way the study of Navier-Stokes equations includes the analysis of the de Rham complex. In particular, the Hodge theory for the de Rham complex enables one to eliminate the pressure from the equations. The Navier-Stokes equations constitute a parabolic system with a nonlinear term which makes sense only for one-forms. A simpler model of dynamics of incompressible viscous fluid is given by Burgers' equation. This work is aimed at the study of invariant structure of the Navier-Stokes equations which is closely related to the algebraic structure of the de Rham complex at step 1. To this end we introduce Navier-Stokes equations related to any elliptic quasicomplex of first order differential operators. These equations are quite similar to the classical Navier-Stokes equations including generalised velocity and pressure vectors. Elimination of the pressure from the generalised Navier-Stokes equations gives a good motivation for the study of the Neumann problem after Spencer for elliptic quasicomplexes. Such a study is also included in the work.We start this work by discussion of Lam{\´e} equations within the context of elliptic quasicomplexes on compact manifolds with boundary. The non-stationary Lam{\´e} equations form a hyperbolic system. However, the study of the first mixed problem for them gives a good experience to attack the linearised Navier-Stokes equations. On this base we describe a class of non-linear perturbations of the Navier-Stokes equations, for which the solvability results still hold.}, language = {en} } @article{MeraTarkhanov2022, author = {Mera, Azal Jaafar Musa and Tarkhanov, Nikolai}, title = {An elliptic equation of finite index in a domain}, series = {Boletin de la Sociedad Matem{\´a}tica Mexicana}, volume = {28}, journal = {Boletin de la Sociedad Matem{\´a}tica Mexicana}, number = {2}, publisher = {Springer International}, address = {New York [u.a.]}, issn = {1405-213X}, doi = {10.1007/s40590-022-00442-7}, pages = {10}, year = {2022}, abstract = {We give an example of first order elliptic equation for a complex-valued function in a plane domain which has a finite number of linearly independent solutions for any right-hand side. No boundary value conditions are thus required.}, language = {en} }