158,636 research outputs found
Differential calculus over double Lie algebroids
The notion of double Lie algebroid was defined by M. Van den Bergh and was
illustrated by the double quasi Poisson case. We give new examples of double
Lie algebroids and develop a differential calculus in that context. We recover
the non commutative de Rham complex and the double Poisson-Lichnerowicz
cohomology (Pichereau-vanWeyer) as particular cases of our construction.Comment: 18 page
Relative polynomial closure and monadically Krull monoids of integer-valued polynomials
Let D be a Krull domain and Int(D) the ring of integer-valued polynomials on
D. For any f in Int(D), we explicitly construct a divisor homomorphism from
[f], the divisor-closed submonoid of Int(D) generated by f, to a finite sum of
copies of (N_0,+). This implies that [f] is a Krull monoid.
For V a discrete valuation domain, we give explicit divisor theories of
various submonoids of Int(V). In the process, we modify the concept of
polynomial closure in such a way that every subset of D has a finite
polynomially dense subset.
The results generalize to Int(S,V), the ring of integer-valued polynomials on
a subset, provided S doesn't have isolated points in v-adic topology.Comment: 12 pages; v.2 contains corrections, in that some necessary conditions
on those subsets S, for which we consider integer-valued polynomials on
subsets, are impose
Implementing the Agenda for Global Action on human resources for health : Analysis from an international tracking survey
Peer reviewedPublisher PD
An empirical central limit theorem in L^1 for stationary sequences
In this paper, we derive asymptotic results for L^1-Wasserstein distance
between the distribution function and the corresponding empirical distribution
function of a stationary sequence. Next, we give some applications to dynamical
systems and causal linear processes. To prove our main result, we give a
Central Limit Theorem for ergodic stationary sequences of random variables with
values in L^1. The conditions obtained are expressed in terms of
projective-type conditions. The main tools are martingale approximations.Comment: 20 page
Review of 13th: A Beautiful and Powerful Wake Up Call
This film review of 13th is featured in the journal Tapestries: Interwoven voices of local and global identities, volume 6
Approximability of the Multiple Stack TSP
STSP seeks a pair of pickup and delivery tours in two distinct networks,
where the two tours are related by LIFO contraints. We address here the problem
approximability. We notably establish that asymmetric MaxSTSP and MinSTSP12 are
APX, and propose a heuristic that yields to a 1/2, 3/4 and 3/2 standard
approximation for respectively Max2STSP, Max2STSP12 and Min2STSP12
Living with water scarcity. A tale from Africa
Sophie Salffner has spent six months in Nigeria doing linguistic fieldwork. She never lived a day without water, but learnt how to manage it in a different way. In this short article, Sophie describes her experience in the world of water scarcity, far away from home and far away from the luxurious daily showers and running tap water of her home country Germany
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The Challenges of collaboration and democratic participation in turbulent and unsettled times
This paper proposes new key ways to thinking about self-organisation in cities in what, I suggest, are increasingly unsettled and turbulent times. The importance of thinking about self-organisation in cities is all the more salient in the current economic and social context where in many parts of the world there is a withdrawal by the state from public involvement and expenditure, which is impacting on urban citizens, particularly those who are vulnerable, in increasing negative ways. Self-organisation is thus an important and key direction for the future, if cities are to remain inclusive, just and responsive to local needs. Yet such self-organisation can only be truly meaningful and effective if it is conducted collaboratively and democratically, involving as many people as possible, particularly those whose voices are not often heard. In so doing, it is also important to recognise that such involvement and democratic participation are not always consensual; rather conflict is inevitable and potentially positive, as people learnt to recognise their differences, which are often implicated in power, and to negotiate solutions together
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