A new method of analysis of degeneracies of arbitrary co-dimension in nonlinear systems of ODEs depending on parameters was suggested. The method is based on the use of variational equations of higher order, which are obtained recursively from the original equations and each other. These equations may be computed with the help of computer algebra systems. Degeneracies are understood in a broad sense. Bifurcations, the loss of stability, geometric peculiarities in the phase space (folds and pleats of the families of solutions) etc.\ may be effectively studied by this method. As an application, the equation of oscillations of the satellite in the plane of its elliptic orbit was considered, for which some new degenerate periodic solutions were found. Besides, the classical center-focus problem was considered. It was shown that all cases ever studied for this problem (i.e. systems with one edge of the Newton polygon) may be investigated by the method. Within this problem, perturbed Hamiltonian system with two edges of the Newton polygon were studied for the first time. Explicit formulas for the asymptotics of the Poincare mapping were obtained.
Biography
Graduated from Faculty of Mathematics and Mechanics of Lomonosov Moscow State University (MSU) in 1981 (Department of Theory of Functions and Functional Analysis). Graduated from postgraduate studies in MSU in 1986 at Department of General Control Problems. Advisor Prof. K. I. Babenko. Ph.D. thesis was defended in 1992. At this time, I am a senior researcher at Keldysh Institute of Applied Mathematics. A list of my works contains 25 titles.
In 1999, I translated from Russian the book "Power Geometry" by Prof. A. D. Bruno. It appeared at "Elsevier", 2000, as "Power Geometry in Algebraic and Differential Equations".
Main publications:
Varin V. P. An analysis of periodic flows in the vicinity of the plane Poiseille flow (with A. L.Afendikov) // Eur. J. Mech., B/Fluids, 10:6, 1991, 577–603.
Varin V. P. Bifurcations of some viscous fluid flow and transition to turbulence (with A. L. Afendikov) // Eur. J. Mech., B/Fluids, 10:2, Suppl., 1991, 13–18.
Varin V. P. The limit problems for the equation of oscillations of a satellite (with A. D. Bruno) // Celestial Mechanics and Dynamical Astronomy, 1997, v. 67, no. 1, pp. 1–40.
Varin V.P. Degeneracies of periodic solutions to the Beletskii equation // Regular & Chaotic Dynamics, 2000, v. 5, no. 3, pp. 38–54.
V. P. Varin, “Some applications of Brun's criterion”, Keldysh Institute preprints, 2022, 014, 22 pp.
9.
V. P. Varin, “Sequence transformations in proofs of irrationality of some fundamental constants”, Zh. Vychisl. Mat. Mat. Fiz., 62:10 (2022), 1587–1614; Comput. Math. Math. Phys., 62:10 (2022), 1559–1585
V. P. Varin, “Computation of periodic solutions to pendulum type systems with a small parameter”, Zh. Vychisl. Mat. Mat. Fiz., 60:12 (2020), 2055–2072; Comput. Math. Math. Phys., 60:12 (2020), 1990–2006
16.
V. P. Varin, “Nonlocal singularities on families of periodic solutions to ordinary differential equations”, Zh. Vychisl. Mat. Mat. Fiz., 60:1 (2020), 57–69; Comput. Math. Math. Phys., 60:1 (2020), 53–64
2019
17.
V. P. Varin, “Pendulum type systems from computer algebra viewpoint”, Keldysh Institute preprints, 2019, 103, 28 pp.
18.
V. P. Varin, “Integration of ODEs on Riemann surfaces with an arbitrary precision”, Keldysh Institute preprints, 2019, 001, 24 pp.
19.
V. P. Varin, “Integration of ordinary differential equations on Riemann surfaces with unbounded precision”, Zh. Vychisl. Mat. Mat. Fiz., 59:7 (2019), 1158–1173; Comput. Math. Math. Phys., 59:7 (2019), 1105–1120
A. D. Bruno, A. B. Batkhin, V. P. Varin, “Computation of the Sets of Stability in Multiparameter Problems”, Keldysh Institute preprints, 2010, 023, 22 pp.
V. P. Varin, A. G. Petrov, “A hydrodynamic model of human cochlea”, Zh. Vychisl. Mat. Mat. Fiz., 49:9 (2009), 1708–1723; Comput. Math. Math. Phys., 49:9 (2009), 1632–1647
V. P. Varin, A. G. Petrov, “A mathematical model of human cochlea”, Keldysh Institute preprints, 2008, 096, 26 pp.
39.
A. D. Bruno, V. P. Varin, “The families c and i of periodic solutions of the restricted problem for $\mu=5\cdot10^{-5}$”, Keldysh Institute preprints, 2008, 022, 26 pp.
40.
V. P. Varin, “Closed families of periodic solutions of the restricted three-body problem”, Keldysh Institute preprints, 2008, 016, 27 pp.
V. P. Varin, “Localization of Degeneracies in Families of Periodic Solutions to an ODE and their Regularization”, Keldysh Institute preprints, 1999, 023
61.
V. P. Varin, “Localization of Degeneracies in Families of Periodic Solutions to an ODE and their Regularization”, Keldysh Institute preprints, 1999, 022
1997
62.
V. P. Varin, “Generalized Periodic Solutions to the Equation of Oscillations of a Satellite”, Keldysh Institute preprints, 1997, 097
63.
V. P. Varin, “The critical subfamilies of the family $K_0$ of periodic solutions to the equation of oscillations of a satellite”, Keldysh Institute preprints, 1997, 020
V. P. Varin, “The Critical Families of Periodic Solutions to the Equation of Oscillations of a Satellite”, Keldysh Institute preprints, 1996, 101
1995
65.
A. D. Bruno, V. P. Varin, “The Second Limit Problem for the Equation of Oscillations of a Satellite”, Keldysh Institute preprints, 1995, 128
66.
A. D. Bruno, V. P. Varin, “The First Limit Problem for the Equation of Oscillations of a Satellite”, Keldysh Institute preprints, 1995, 124
1990
67.
A. L. Afendikov, V. P. Varin, “A study of self-oscillating regimes that are close to the
Poiseuille flow in a two-dimensional channel”, Dokl. Akad. Nauk SSSR, 313:6 (1990), 1407–1412; Dokl. Math., 35:8 (1990), 720–723