Search results for "Combinatorics"
showing 10 items of 1770 documents
On the WGSC Property in Some Classes of Groups
2009
The property of quasi-simple filtration (or qsf) for groups has been introduced in literature more than 10 years ago by S. Brick. This is equivalent, for groups, to the weak geometric simple connectivity (or wgsc). The main interest of these notions is that there is still not known whether all finitely presented groups are wgsc (qsf) or not. The present note deals with the wgsc property for solvable groups and generalized FC-groups. Moreover, a relation between the almost-convexity condition and the Tucker property, which is related to the wgsc property, has been considered for 3-manifold groups.
Area-minimizing cones in the Heisenberg group H
2021
We present a characterization of minimal cones of class \(C^2\) and \(C^1\) in the first Heisenberg group \(\mathbf{H}\), with an additional set of examples of minimal cones that are not of class \(C^1\).
Commutators of linear and bilinear Hilbert transforms
2003
Let α ∈ R \alpha \in \mathbb {R} , and let H α ( f , g ) ( x ) = 1 π p . v . ∫ f ( x − t ) g ( x − α t ) d t t H_\alpha (f,g)(x)=\frac {1}{\pi } p.v. \int f(x-t)g(x-\alpha t)\frac {dt}{t} and H f ( x ) = 1 π p . v . ∫ f ( x − t ) d t t Hf(x)= \frac {1}{\pi } p.v.\int f(x-t)\frac {dt}{t} denote the bilinear and linear Hilbert transforms, respectively. It is proved that, for 1 > p > ∞ 1>p>\infty and α 1 ≠ α 2 \alpha _1\ne \alpha _2 , H α 1 − H α 2 H_{\alpha _1}-H_{\alpha _2} maps L p × B M O L^p\times BMO into L p L^{p} and it maps B M O × L p BMO \times L^p into L p L^{p} if and only if sign ( α 1 ) = sign ( α 2 ) \operatorname {sign}(\alpha _1)=\operatorname {sign}(\alpha _2…
Absolute continuity of mappings with finite geometric distortion
2015
Suppose that ⊂ R n is a domain with n ≥ 2. We show that a continuous, sense-preserving, open and discrete mapping of finite geometric outer distortion with KO(·,f) ∈ L 1/(n 1) loc () is absolutely continuous on almost every line parallel to the coordinate axes. Moreover, if U ⊂ is an open set with N(f,U) 0 depends only on n and on the maximum multiplicity N(f,U).
Muséo-parcs et réenchantement de l’expérience muséale : le cas de la Cité des Arts et des Sciences de Valencia
2010
The museum offer undergoes at present profound transformations. Beyond the traditional structures which do not any more hesitate to use innovative museographies and to slide in the sphere of the leisure activities, it seems to develop a new sector, halfway between museums and amusement parks called museopark. The aim of this article is to analyze an example of this hybrid offer, the City of Arts and Science in Valencia (Spain), fitting very well with the edutainment logic and to understand the structuring elements and the borrowings made in of the amusement parks. After the presentation of theoretical foundations underlying the definition of experiential museums, we expose our case study, b…
On permutations of class sums of alternating groups
1997
We prove a result concerning the class sums of the alternating group An; as a consequence we deduce that if θ is a normalized automorphism of the integral group ring then there exists such that is the identity on , where Sn:is the symmetric group and is the center of
The exact bounds for the degree of commutativity of a p-group of maximal class, I
2002
Abstract The first major study of p-groups of maximal class was made by Blackburn in 1958. He showed that an important invariant of these groups is the ‘degree of commutativity.’ Recently (1995) Fernandez-Alcober proved a best possible inequality for the degree of commutativity in terms of the order of the group. Recent computations for primes up to 43 show that sharper results can be obtained when an additional invariant is considered. A series of conjectures about this for all primes have been recorded in [A. Vera-Lopez et al., preprint]. In this paper, we prove two of these conjectures.
Sufficient conditions for supersolubility of finite groups
1998
Abstract In this paper sufficient conditions for the supersolubility of finite groups are given under the assumption that the maximal subgroups of Sylow subgroups of the group and the maximal subgroups of Sylow subgroups of the Fitting subgroup are well-situated in the group. That will improve earlier results of Srinivasan [7], Asaad et al. [1] and Ballester-Bolinches [2].
ON A PERMUTABILITY PROPERTY OF SUBGROUPS OF FINITE SOLUBLE GROUPS
2010
The structure and embedding of subgroups permuting with the system normalizers of a finite soluble group are studied in the paper. It is also proved that the class of all finite soluble groups in which every subnormal subgroup permutes with the Sylow subgroups is properly contained in the class of all soluble groups whose subnormal subgroups permute with the system normalizers while this latter is properly contained in the class of all supersoluble groups.
Quelles stratégies développer pour éviter une communication intrusive sur les TIC ?
2007
Les TIC font partie de la panoplie des outils du marketing relationnel. Les liens qu'elles permettent d'etablir avec les consommateurs risquent toutefois de s'exposer a des mecanismes de resistance a l'invasion publicitaire. Ces resistances sont possibles mais non ineluctables. Elles sont moindres lorsque les strategies de communication retenues paraissent moins intrusives.