6,920 research outputs found
Cocycle deformations for liftings of quantum linear spaces
Let be a Hopf algebra over a field of characteristic 0 and suppose
there is a coalgebra projection from to a sub-Hopf algebra that
splits the inclusion. If the projection is -bilinear, then is isomorphic
to a biproduct R #_{\xi}H where is called a pre-bialgebra with
cocycle in the category . The cocycle maps to . Examples of this situation include the liftings of pointed
Hopf algebras with abelian group of points as classified by
Andruskiewitsch and Schneider [AS1]. One asks when such an can be twisted
by a cocycle to obtain a Radford biproduct. By
results of Masuoka [Ma1, Ma2], and Gr\"{u}nenfelder and Mastnak [GM], this can
always be done for the pointed liftings mentioned above.
In a previous paper [ABM1], we showed that a natural candidate for a twisting
cocycle is {} where is a total
integral for and is as above. We also computed the twisting cocycle
explicitly for liftings of a quantum linear plane and found some examples where
the twisting cocycle we computed was different from {}. In
this note we show that in many cases this cocycle is exactly
and give some further examples where this is not the case. As well we extend
the cocycle computation to quantum linear spaces; there is no restriction on
the dimension
Use of Kriging Technique to Study Roundabout Performance
Road intersections are dangerous places because of the many conflicting points between
motorized and nonmotorized vehicles. In the case of defined traffic volume, several research
groups have proved that roundabouts reduced the number of injuries and fatal accident cases.
In recent years, many countries have adopted roundabouts as a standard design solution for
both urban and rural roads. Several recent studies have investigated the performance of
roundabouts, including some with models that calculated the entering flow (Q sub e) as a
function of the circulating flow (Q sub c). Most existing models have been constructed with the
use of linear or exponential statistical regression. The interpolative techniques in classical
statistics are based on the use of canonical forms (linear or polynomial) that completely ignore
the correlation law between collected data. As such, the determined interpolation stems from
the assumption that the data represent a random sample. In the research reported in this
paper, a geostatistical approach was considered: the relationship Q sub e versus Q sub c is
supposed to be a regionalized phenomenon. According to that supposition, collected data do
not represent a random sample of values but are supposed to be related to each other with a
defined law. This recognition allows the realization of interpolation on the basis of the real law of
the phenomenon. This paper discusses the fundamental theories, the applied operating
procedures, and the first results obtained in modeling the Q sub e versus Q sub c relationship
with the application of geostatistics
Designing the venue logistics management operations for a World Exposition
World Expositions, due to their size and peculiar features, pose a number of logistics challenges. This paper aims at developing a design framework for the venue logistics management (VLM) operations to replenish food products to the event site, through a combination of qualitative and quantitative research approaches. First, an in-depth interview methodology, combined with the outcomes of a literature review, is adopted for defining the key variables for the tactical and operational set-up of the VLM system. Second, a quantitative approach is developed to define the necessary logistics resources. The framework is then applied to the case of Milan 2015 World Exposition. It is the first time that such a design framework for a World Exposition is presented: the originality of this research lies in the proposal of a systematic approach that adds to the experiential practices constituting the current body of knowledge on event logistics
Quasi-bialgebra Structures and Torsion-free Abelian Groups
We describe all the quasi-bialgebra structures of a group algebra over a
torsion-free abelian group. They all come out to be triangular in a unique way.
Moreover, up to an isomorphism, these quasi-bialgebra structures produce only
one (braided) monoidal structure on the category of their representations.
Applying these results to the algebra of Laurent polynomials, we recover two
braided monoidal categories introduced in \cite{CG} by S. Caenepeel and I.
Goyvaerts in connection with Hom-structures (Lie algebras, algebras,
coalgebras, Hopf algebras)
Polynomial growth of discrete quantum groups, topological dimension of the dual and *-regularity of the Fourier algebra
Banica and Vergnioux have shown that the dual discrete quantum group of a
compact simply connected Lie group has polynomial growth of order the real
manifold dimension. We extend this result to a general compact group and its
topological dimension, by connecting it with the Gelfand-Kirillov dimension of
an algebra. Furthermore, we show that polynomial growth for a compact quantum
group G of Kac type implies *-regularity of the Fourier algebra A(G), that is
every closed ideal of C(G) has a dense intersection with A(G). In particular,
A(G) has a unique C*-norm.Comment: to appear in Annales de l'Institut Fourie
Eco-efficient supply chain networks: Development of a design framework and application to a real case study
© 2015 Taylor & Francis. This paper presents a supply chain network design framework that is based on multi-objective mathematical programming and that can identify 'eco-efficient' configuration alternatives that are both efficient and ecologically sound. This work is original in that it encompasses the environmental impact of both transportation and warehousing activities. We apply the proposed framework to a real-life case study (i.e. Lindt & Sprüngli) for the distribution of chocolate products. The results show that cost-driven network optimisation may lead to beneficial effects for the environment and that a minor increase in distribution costs can be offset by a major improvement in environmental performance. This paper contributes to the body of knowledge on eco-efficient supply chain design and closes the missing link between model-based methods and empirical applied research. It also generates insights into the growing debate on the trade-off between the economic and environmental performance of supply chains, supporting organisations in the eco-efficient configuration of their supply chains
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