Vulpe Nicolae Ivanovich

Publications in Math-Net.Ru

1. The codimension of the phase portraits for degenerate quadratic differential systems
   
   Bul. Acad. Ştiinţe Repub. Mold. Mat., 2024, no. 3,  29–53
2. The family of cubic differential systems with two real and two complex distinct infinite singularities and invariant straight lines of the type $(2,2,2)$
   
   Bul. Acad. Ştiinţe Repub. Mold. Mat., 2024, no. 1-2,  84–99
3. The bifurcation diagram of the configurations of invariant lines of total multiplicity exactly three in quadratic vector fields
   
   Bul. Acad. Ştiinţe Repub. Mold. Mat., 2023, no. 1,  42–77
4. The topological classification of a family of quadratic differential systems in terms of affine invariant polynomials
   
   Bul. Acad. Ştiinţe Repub. Mold. Mat., 2019, no. 2,  41–55
5. Geometric configurations of singularities for quadratic differential systems with total finite multiplicity lower than 2
   
   Bul. Acad. Ştiinţe Repub. Mold. Mat., 2013, no. 1,  72–124
6. A complete classification of quadratic differential systems according to the dimensions of $Aff(2,\mathbb R)$-orbits
   
   Bul. Acad. Ştiinţe Repub. Mold. Mat., 2009, no. 2,  29–54
7. Integrals and phase portraits of planar quadratic differential systems with invariant lines of total multiplicity four
   
   Bul. Acad. Ştiinţe Repub. Mold. Mat., 2008, no. 1,  27–83
8. Classification of quadratic systems with a symmetry center and simple infinite singular points
   
   Bul. Acad. Ştiinţe Repub. Mold. Mat., 2003, no. 1,  102–119
9. Affine-invariant conditions for the topological discrimination of quadratic Hamiltonian differential systems
   
   Differ. Uravn., 34:3 (1998),  298–302
10. Topological classification of a quadratic system with a four-fold singular point
    
    Differ. Uravn., 29:10 (1993),  1669–1674
11. The number and multiplicity of singular points of a quadratic differential system
    
    Dokl. Akad. Nauk, 323:1 (1992),  9–12
12. Coefficient conditions for the number and multiplicity of singular points of a quadratic differential system
    
    Differ. Uravn., 27:4 (1991),  572–577
13. The problem of the center “in the large” for a general quadratic system
    
    Dokl. Akad. Nauk SSSR, 311:4 (1990),  777–780
14. Solution of a problem of the center “in the large” for a general quadratic differential system
    
    Differ. Uravn., 25:11 (1989),  1856–1862
15. Centro-affine invariant conditions for the existence of a center of a differential system with cubic nonlinearities
    
    Dokl. Akad. Nauk SSSR, 301:6 (1988),  1297–1301
16. Construction of a minimal complete system of orthogonal invariants for a two-dimensional system of differential equations
    
    Dokl. Akad. Nauk SSSR, 269:6 (1983),  1299–1302
17. Minimal complete system of orthogonal invariants of a two-dimensional differential system
    
    Differ. Uravn., 19:4 (1983),  564–569
18. Affine-invariant conditions for topological distinction of quadratic systems in the presence of a center
    
    Differ. Uravn., 19:3 (1983),  371–379
19. The minimal basis of comitants of a differential system with quadratic nonlinearities
    
    Differ. Uravn., 17:11 (1981),  1955–1963
20. Polynomial basis of centroaffine comitants of a homogeneous cubic differential system
    
    Differ. Uravn., 17:9 (1981),  1682–1684
21. A polynomial basis for the centro-affine concomitants of a differential system
    
    Dokl. Akad. Nauk SSSR, 250:5 (1980),  1033–1037
22. Construction of a polynomial basis of comitants of a differential system
    
    Differ. Uravn., 15:8 (1979),  1399–1410
23. The number of linearly independent compacta of a system of differential equations
    
    Differ. Uravn., 15:6 (1979),  963–973
24. Geometric classification of a quadratic differential system
    
    Differ. Uravn., 13:5 (1977),  803–814
25. A minimal polynomial base of the affine invariants of a quadratic system
    
    Differ. Uravn., 11:5 (1975),  918–920
26. Affine classification of a quadratic system
    
    Differ. Uravn., 10:12 (1974),  2111–2124


27. Professor Boris Şcerbacov - 100th anniversary
    
    Bul. Acad. Ştiinţe Repub. Mold. Mat., 2024, no. 1-2,  3–5
28. Konstantin Sergeevich Sibirskiǐ
    
    Differ. Uravn., 26:6 (1990),  1098–1100