| Реферат: | eng: We study the geometric properties of solutions to degenerate parabolic equations of the form v(t) = f(nu, nu(x), nu nu(xx)), which occur in problems of a nonstationary filtration type, the turbulence theory, and other branches of physics. We prove that the concavity of a solution profile preserves and a concave profile forms in a finite time. To prove it we use the method, which is based on studying equipotential curves. The obtained regularities in the solution behaviour are important for testing numerical experiments.
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