Search results for "rings"
showing 10 items of 434 documents
Nanorings and rods interconnected by self-assembly mimicking an artificial network of neurons
2013
[EN] Molecular electronics based on structures ordered as neural networks emerges as the next evolutionary milestone in the construction of nanodevices with unprecedented applications. However, the straightforward formation of geometrically defined and interconnected nanostructures is crucial for the production of electronic circuitry nanoequivalents. Here we report on the molecularly fine-tuned self-assembly of tetrakis-Schiff base compounds into nanosized rings interconnected by unusually large nanorods providing a set of connections that mimic a biological network of neurons. The networks are produced through self-assembly resulting from the molecular conformation and noncovalent intermo…
Temperature dependent optical properties of stacked InGaAs/GaAs quantum rings
2008
4 páginas, 3 figuras, 2 tablas.-- MADICA 2006 Conference, Fifth Maghreb-Europe Meeting on Materials and their Applicatons for Devices and Physical, Chemical and Biological Sensors
Jordan Decompositions of Tensors
2022
We expand on an idea of Vinberg to take a tensor space and the natural Lie algebra which acts on it and embed them into an auxiliary algebra. Viewed as endomorphisms of this algebra we associate adjoint operators to tensors. We show that the group actions on the tensor space and on the adjoint operators are consistent, which endows the tensor with a Jordan decomposition. We utilize aspects of the Jordan decomposition to study orbit separation and classification in examples that are relevant for quantum information.
Real structures on nilpotent orbit closures
2021
We determine the equivariant real structures on nilpotent orbits and the normalizations of their closures for the adjoint action of a complex semisimple algebraic group on its Lie algebra.
Algèbres et cogèbres de Gerstenhaber et cohomologie de Chevalley–Harrison
2009
Resume Un prototype des algebres de Gerstenhaber est l'espace T poly ( R d ) des champs de tenseurs sur R d muni du produit exterieur et du crochet de Schouten. Dans cet article, on decrit explicitement la structure de la G ∞ algebre enveloppante d'une algebre de Gerstenhaber. Cette structure permet de definir une cohomologie de Chevalley–Harrison sur cette algebre. On montre que cette cohomologie a valeur dans R n'est pas triviale dans le cas de la sous algebre de Gerstenhaber des tenseurs homogenes T poly hom ( R d ) .
Graded Poisson structures on the algebra of differential forms
1995
We study the graded Poisson structures defined on Ω(M), the graded algebra of differential forms on a smooth manifoldM, such that the exterior derivative is a Poisson derivation. We show that they are the odd Poisson structures previously studied by Koszul, that arise from Poisson structures onM. Analogously, we characterize all the graded symplectic forms on ΩM) for which the exterior derivative is a Hamiltomian graded vector field. Finally, we determine the topological obstructions to the possibility of obtaining all odd symplectic forms with this property as the image by the pullback of an automorphism of Ω(M) of a graded symplectic form of degree 1 with respect to which the exterior der…
On Drazin invertibility
2008
The left Drazin spectrum and the Drazin spectrum coincide with the upper semi-B-Browder spectrum and the B-Browder spectrum, respectively. We also prove that some spectra coincide whenever T or T* satisfies the single-valued extension property.
On Almost Nilpotent Varieties of Linear Algebras
2020
A variety \(\mathcal {V}\) is almost nilpotent if it is not nilpotent but all proper subvarieties are nilpotent. Here we present the results obtained in recent years about almost nilpotent varieties and their classification.
Automorphisms of the semigroup of endomorphisms of free associative algebras
2005
Let $A=A(x_{1},...,x_{n})$ be a free associative algebra in $\mathcal{A}$ freely generated over $K$ by a set $X=\{x_{1},...,x_{n}\}$, $End A$ be the semigroup of endomorphisms of $A$, and $Aut End A$ be the group of automorphisms of the semigroup $End A$. We investigate the structure of the groups $Aut End A$ and $Aut \mathcal{A}^{\circ}$, where $\mathcal{A}^{\circ}$ is the category of finitely generated free algebras from $\mathcal{A}$. We prove that the group $Aut End A$ is generated by semi-inner and mirror automorphisms of $End F$ and the group $Aut \mathcal{A}^{\circ}$ is generated by semi-inner and mirror automorphisms of the category $\mathcal{A}^{\circ}$. This result solves an open …
CHEVALLEY COHOMOLOGY FOR KONTSEVICH'S GRAPHS
2005
We introduce the Chevalley cohomology for the graded Lie algebra of polyvector fields on $R^d$. This cohomology occurs naturally in the problem of construction and classification of fomalities on the sapce $ R^d$. Considering only graphs formalities, we define the Chevalley cohomology directly on spaces of graphs. We obtain some simple expressions for the Chevalley coboundary operator and we give examples and applications.