Количество страниц: 6 с.
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Антипов, А. В. Разработка оборудования для сублимационной сушки с использованием естественного холода в Республике Саха (Якутия) / А. В. Антипов, Г. П. Власенко, Ю. Ж. Дондоков ; Международная Академия холода, ООО "Холодильные Системы машиностроение", Московский энергетический институт, Арктический государственный агротехнологический университет // Вестник АГАТУ. - 2022. - N 4 (8). - C. 43-48.
Количество страниц: 16 с.
The article is devoted to studying one of the sections of nonclassical differential equations, namely, matters concerned with solvability of parabolic equations with changing second-order time direction. As is known, in ordinary boundary-value problems for strictly parabolic equations, the smoothness of the initial and boundary conditions completely ensures that the solutions belong to the Holder spaces, but in the case of equations with changing time direction, the smoothness of the initial and boundary conditions does not ensure that the solutions belong to these spaces. S.A. Tersenov (for a model parabolic equation with changing time direction) and S.G. Pyatkov (for a more general second-order equation) obtained the necessary and sufficient conditions for solvability of the corresponding mixed problems in Holder spaces. In so doing, they always assumed the initial and boundary conditions being equal to zero. Cases in which the initial and boundary conditions belong to Banach spaces are considered. The functional spaces in which the solutions must be sought are introduced. Relevant a priori estimates, which make it possible to obtain the solvability conditions for these problems, are obtained. The properties of the obtained solutions have been studied. In particular, the equivalence of the Riesz and Littlewood-Paley conditions similar to the conditions for solutions of strictly elliptic and strictly parabolic second order equations is established. A unique solvability of the first mixed problem with boundary and initial functions from the Banach space has been proved.
Петрушко, И. М. О первой смешанной задаче в банаховых пространствах для вырождающихся уравнений с меняющимся направлением времени / И. М. Петрушко, М. И. Петрушко // Математические заметки СВФУ. — 2018. — Т. 25, N 4 (100), октябрь-декабрь. — С. 45-59.
DOI: 10.25587/SVFU.2018.100.20553
Количество страниц: 20 с.
We establish the necessary and sufficient conditions for the solution of the second-order parabolic equation in a stellar domain with a lateral boundary in the class degenerate on the boundary of the domain, to have an average limit on the lateral surface of the cylindrical domain and the limit in the mean on its lower base. Also, we study the unique solvability of the first mixed problem for such equations in the case when the boundary and initial functions belong to spaces of the type. The closest to the questions under consideration are the theorems of Riesz and Littlewood and Paley, in which criteria are given for the limit values in p > 1, of functions analytic in the unit disk. Further development of this topic for uniformly elliptic equations was obtained in the works V. P. Mikhailov and A. K. Gushchin. The boundary smoothness condition can be weakened, as was shown by I. M. Petrushko. Under the weakest restrictions on the smoothness of the boundary (and on the coefficients of the equation), the criteria for the existence of a boundary value were established in by A. K. Gushchin. In this case, all directions of the acceptance of boundary values for uniformly elliptic equations turn out to be equal, the solution has the property similar to the property of continuity with respect to the set of variables. In the case of degeneracy of the equation on the boundary of the domain, when the directions are not equal, the situation is more complicated. In this case, the formulation of the first boundary value problem is determined by the type of degeneracy. When the values of the corresponding quadratic form of the degenerate elliptic equation on the normal vector are different from zero (Tricomi type degeneracy), the Dirichlet problem is well-posed and the properties of such degenerate equations are very close to the properties of uniformly elliptic equations. In particular, in this situation analogues of the Riesz and Littlewood-Paley theorems are valid.
Капицына, Т. В. О существовании граничных и начальных значений для вырождающихся параболических уравнений в звездных областях / Т. В. Капицына // Математические заметки СВФУ. — 2018. — Т. 25, N 4 (100), октябрь-декабрь. — С. 15-33.
DOI: 10.25587/SVFU.2018.100.20551