Cherkas Leonid Antonovich

Publications in Math-Net.Ru

1. Spline approximations in the problem of estimating the number of limit cycles of autonomous systems on the plane
   
   Differ. Uravn., 42:2 (2006),  213–220
2. On the Coppel Problem for Quadratic Systems with a Fine Focus
   
   Differ. Uravn., 41:8 (2005),  1100–1104
3. Extrema of the Andronov–Hopf function of a polynomial Lienard system
   
   Differ. Uravn., 41:1 (2005),  50–60
4. Normal-Size Limit Cycles of Quadratic Systems with a Structurally Unstable Focus
   
   Differ. Uravn., 40:8 (2004),  1076–1084
5. Quadratic systems with limit cycles of normal size
   
   Bul. Acad. Ştiinţe Repub. Mold. Mat., 2003, no. 1,  31–46
6. An Estimate of the Number of Limit Cycles via Critical Points of Conditional Extremum
   
   Differ. Uravn., 39:10 (2003),  1334–1342
7. A Precise Estimate of the Number of Limit Cycles of Autonomous Systems on the Plane
   
   Differ. Uravn., 39:6 (2003),  759–768
8. Curves of Separatrix Cycles of a Quadratic System. The Case of Three Antisaddles and One Saddle
   
   Differ. Uravn., 38:3 (2002),  313–318
9. A Special Dulac Function for a Quadratic System on the Plane
   
   Differ. Uravn., 37:4 (2001),  481–487
10. Algebraic Aspects of Finding a Dulac Function for Polynomial Autonomous Systems on the Plane
    
    Differ. Uravn., 37:3 (2001),  384–390
11. A Dulac function in a half-plane in the form of a polynomial of the second degree for a quadratic system
    
    Differ. Uravn., 34:10 (1998),  1346–1348
12. A second-degree polynomial Dulac function for a cubic system on the plane
    
    Differ. Uravn., 33:10 (1997),  1435–1436
13. The Dulac function for polynomial autonomous systems on a plane
    
    Differ. Uravn., 33:5 (1997),  689–699
14. The curve of separatrix cycles of an autonomous quadratic system in the plane. The case of two anti-saddles
    
    Differ. Uravn., 32:1 (1996),  15–21
15. Bifurcations of limit cycles of a quadratic system with two singular points and two parameters that rotate the field
    
    Differ. Uravn., 23:9 (1987),  1544–1553
16. Limit cycles of autonomous systems with phase space $\mathbf C^2$
    
    Differ. Uravn., 23:5 (1987),  848–851
17. On series expansion of an Andronov–Hopf manifold of a quadratic system in the plane
    
    Differ. Uravn., 23:2 (1987),  278–282
18. Absence of limit cycles around a triple focus in a quadratic system in a plane
    
    Differ. Uravn., 22:11 (1986),  2015–2017
19. On the question of the analyticity of a manifold that defines limit cycles
    
    Differ. Uravn., 18:5 (1982),  839–845
20. Bifurcations of limit cycles of a quadratic system with a change of parameter which rotates the field
    
    Differ. Uravn., 17:11 (1981),  2002–2016
21. Two remarks with respect to conditions for a center
    
    Differ. Uravn., 17:9 (1981),  1709–1712
22. Structure of the sequence function in the neighborhood of a separatrix cycle during perturbation of an analytic autonomous system on the plane
    
    Differ. Uravn., 17:3 (1981),  469–478
23. Conditions for a center for the equation $yy'=\sum_{i=0}^3 p_i(x)y^i$
    
    Differ. Uravn., 14:9 (1978),  1594–1600
24. Methods for estimating the number of limit cycles of autonomous systems
    
    Differ. Uravn., 13:5 (1977),  779–802
25. Conditions for the center for a certain equation
    
    Differ. Uravn., 13:2 (1977),  271–275
26. Absence of cycles in the equation $y'=Q_2(x,y)/P_2(x,y)$, with a focus of third degree of structural instability
    
    Differ. Uravn., 12:12 (1976),  2281–2282
27. Integral curves of a certain class of differential equations that have a center
    
    Differ. Uravn., 12:11 (1976),  2102–2104
28. The number of limit cycles of a certain second order autonumous system
    
    Differ. Uravn., 12:5 (1976),  944–946
29. Conditions for a center for a certain Liénard equation
    
    Differ. Uravn., 12:2 (1976),  292–298
30. Conditions for a center for equations $y'=(Q_1+Q_n)/(P_1+P_n)$
    
    Differ. Uravn., 11:12 (1975),  2177–2182
31. Über Grenzzyklen einer quadratischen Differentialgleichung
    
    Differ. Uravn., 10:5 (1974),  947–949
32. Conditions for a center for the equation $P_3(x)yy'=\sum_{i=0}^2P_i(x)y^i$
    
    Differ. Uravn., 10:2 (1974),  367–368
33. The cycles of the equation $y'=Q_2(x,y)/P_2(x,y)$
    
    Differ. Uravn., 9:8 (1973),  1432–1437
34. The absence of limit cycles of a certain differential equation
    
    Differ. Uravn., 8:12 (1972),  2271–2273
35. Conditions for the center for certain equations of the form $yy'=P(x)+Q(x)y+R(x)y^2$
    
    Differ. Uravn., 8:8 (1972),  1435–1439
36. The limit cycles of certain differential equations
    
    Differ. Uravn., 8:7 (1972),  1207–1213
37. Some tests for the absence or uniqueness of limit cycles
    
    Differ. Uravn., 6:7 (1970),  1170–1178
38. The absence of limit cycles for a certain differential equation that has a structurally unstable focus
    
    Differ. Uravn., 6:5 (1970),  779–783
39. The singular cycles of the equation $\frac{dy}{dx}=\frac{P(x,y)}{xy}$, where $P(x,y)$, is a second degree polynomial
    
    Differ. Uravn., 4:12 (1968),  2281–2285
40. The stability of singular cycles
    
    Differ. Uravn., 4:6 (1968),  1012–1017
41. Stability of a singular cycle in the critical case
    
    Differ. Uravn., 3:7 (1967),  1060–1069
42. Perturbations of a differential equation
    
    Differ. Uravn., 3:5 (1967),  781–786
43. On complex cycles for a certain differential equation
    
    Differ. Uravn., 1:2 (1965),  182–186


44. Nikolaǐ Pavlovich Erugin (on the ninetieth anniversary of his birth)
    
    Differ. Uravn., 33:5 (1997),  579–582
45. Konstantin Sergeevich Sibirskiǐ
    
    Differ. Uravn., 26:6 (1990),  1098–1100