arXiv subjects
Publications and source records attributed to Yahya N'Dao.
In this paper, we define the complex dimension of any additive subgroup of R^{n}$which generalize the euclidien dimension given for the vector space. We give an explicit method to calculate this dimension.
In this paper, we study the action on C^n of any group G of holomorphic diffeomorphisms (automorphisms) of C^n fixing 0. Suppose that there is x in C^n, having an orbit which generates C^n and also E(x)=C^n, where E(x) is the vector space generated by L_{G}={D_{0}fx, f in G }. We give an important condition so that an orbit G(x) is isomorphic (by linear map) to the orbit L_{G}(x)of the linear group L_{G}. More if G is abelian, we prove the existence of a G-invariant open set U, dense in C^n, in which every orbit O is relatively minimal (i.e. the closure of O in U is a closed non empty, G-invariant set and has no proper subset with these properties). Moreover, if G has a dense orbit in C^n then every orbit of U is dense in C^n.
We give a characterization of hypercyclic using (locally hypercyclic) of semigroup G of affine maps of C^n. We prove the existence of a G-invariant open subset of C^n in which any locally hypercyclic orbit is dense in C^n.
We give a characterization of hypercyclic abelian semigroup G of affine maps on C^n. If G is finitely generated, this characterization is explicit. We prove in particular that no abelian group generated by n affine maps on C^n has a dense orbit.
In this paper, we prove that the minimal number of affine maps on C^n, required to form a hypercyclic abelian semigroup on C^n is n+1. We also prove that the action of any abelian group finitely generated by affine maps on C^n, is never k-transitive for k>=2.
In this paper, we define a new structure analogous to group, called partial group. This structure concerns the partial stability by the composition inner law. We generalize the three isomorphism theorems for groups to partial groups.
In this paper, we introduce the notion of regular action of any abelian subgroup G of $Diff^{1}(C^n) on C^n (i.e. the closure of every orbit of G in some open set is a topological sub-manifold of C^n). We prove that if G fixes 0 and dim(vect(L_{G}) =n, then the action of G, can not be p-chaotic for every 0<= p <=n-1. (i.e. If G has a dense orbit then the set of all regular orbit with order p can not be dense in C^{n}), where vect(L_{G}) is the vector space generated by all Df_{0}, f in G. Moreover, weprove that the action of any abelian lie subgroup of Diff^{1}(C^{n}), is regular.
In this paper, we give a characterization for any abelian subgroup G of a lie group of diffeomorphisms maps of C^n, having a somewhere dense orbit G(x), x in C^n: G(x) is somewhere dense in C^n if and only if there are f_{1},....,f_{2n+1 in exp^{-1}(G) such that f_{2n+1} in vect(f_{1},...,f_{2n}) and Z.f_{1}(x)+....+Z.f_{2n+1}(x) is dense subgroup of C^n, where vect(f_{1},....,f_{2n}) is the vector space over R generated by f_{1},....,f_{2n}.
In this paper we study the action of non abelian subgroup G generated by affine homotheties on C^n. We prove that there exist a subgroup H of C\{0}, a G-invariant affine subspace E of C^n and b in E such that the closure of any orbit G(z) is equal to H(z-a)+E, z in C^n. In particular, every orbit in E is dense in it. Moreover, if the complementary U=C^n \E is non empty, every orbit of U is minimal in it.
In this paper, we study the action of non abelian group G generated by affine homotheties on R^n. We prove that G satisfies one of the following properties: (i) there exist a subgroup F_{G} of R\{0} containing 0 in its closure, a G-invariant affine subspace E_{G} of R^n and a in E_{G} such that for every x in R^n the closure of the orbit G(x) is equal to F_{G} .(x - a) +E_{G}. In particular, G(x) is dense in E_{G} for every x in E_{G} and every orbit of U = R^n\E_{G} is minimal in U. (ii) there exists a closed subgroup H_{G} of R^n and a in R^n such that for every x in R^n, the closure of the orbit G(x) is equal to the union of (x + H_{G}) and (-x + a + H_{G}).
In this paper, we study the action of non abelian group G generated by affine homotheties on R^n. We prove that G satisfies one of the following properties: (i) there exist a subgroup F_{G} of R\{0} containing 0 in its closure, a G-invariant affine subspace E_{G} of R^n and a in E_{G} such that for every x in R^n the closure of the orbit G(x) is equal to F_{G} .(x - a) +E_{G}. In particular, G(x) is dense in E_{G} for every x in E_{G} and every orbit of U = R^n\E_{G} is minimal in U. (ii) there exists a closed subgroup H_{G} of R^n and a in R^n such that for every x in R^n, the closure of the orbit G(x) is equal to the union of (x + H_{G}) and (-x + a + H_{G}).