Authors: Şubă Alexandru, Silvia Turuta
Abstract
In this article, we study the real planar cubic differential systems with a
non-degenerate monodromic critical point M 0 . In the cases when the algebraic multiplicity m(Z) = 5 or m(l
1) + m(Z) ≥ 5, where Z = 0 is the line at infinity and l
1 = 0 is an affine real invariant straight line, we prove that the critical point M
0 is of the center type if and only if the first Lyapunov quantity vanishes. More over, if m(Z) = 5 (respectively, m(l
1) + m(Z) ≥ 5, m(l
1) ≥ j, j = 2,3) then M
0 is a center if the cubic systems have a polynomial first integral (respectively, an integrating factor of the form 1/l
1j).
Vladimir Andrunachievici Institute of Mathematics
and Computer Science
5 Academiei str., Chisinau, MD 2028, Moldova
Tiraspol State University
5 Gh. Iablocichin str., Chisinau, MD-2069, Moldova
E-mail: ,
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