6 citations · 6 across the 1 of their papers we have counts for
7 papers
Differential equations invariant under conditional symmetries
Decio Levi, Miguel Angel Rodriguez, Zora Thomova
Nonlinear PDE's having {\bf given} conditional symmetries are constructed. They are obtained starting from the invariants of the "conditional symmetry" generator and imposing the e…
Lie group analysis of a generalized Krichever-Novikov differential-difference equation
Decio Levi, Eugenio Ricca, Zora Thomova +1
The symmetry algebra of the differential--difference equation where , and are…
Contact transformations for difference schemes
Decio Levi, Zora Thomova, Pavel Winternitz
We define a class of transformations of the dependent and independent variables in an ordinary difference scheme. The transformations leave the solution set of the system invariant…
Are there Contact Transformations for Discrete Equations?
Decio Levi, Zora Thomova, Pavel Winternitz
We define infinitesimal contact transformations for ordinary difference schemes as transformations that depend on lattice points and can be integrated to form a…
Subgroup type coordinates and the separation of variables in Hamilton-Jacobi and Schrődinger equations
E. G. Kalnins, Z. Thomova, P. Winternitz
Separable coordinate systems are introduced in the complex and real four-dimensional flat spaces. We use maximal Abelian subgroups to generate coordinate systems with a maximal num…
Maximal Abelian Subalgebras of e(p,q) algebras
Zora Thomova, Pavel Winternitz
Maximal abelian subalgebras of one of the classical real inhomogeneous Lie algebras are constructed, namely those of the pseudoeuclidean Lie algebra e(p,q). Use is made of the semi…