Search results for "metric"
showing 10 items of 10138 documents
Developing Primary School Students’ Formal Geometric Definitions Knowledge by Connecting Origami and Technology
2019
In this paper, we present opportunities with the uses of origami and technology, in our case GeoGebra, in teaching formal geometric definitions for fifth-grade primary school students (11-12yrs). Applying origami in mathematical lessons is becoming to be recognized as a valuable tool for improving students’ mathematical knowledge. In previous studies, we developed origami and technology activities for high-school mathematics, but we wanted to explore if such approach would work in primary school as well. For this reason, we chose a flat origami model оf the crane and we used this model to introduce students to basic geometrical notions and definitions, such as points, lines, intersections o…
Intrinsic Lipschitz Graphs and Vertical β-Numbers in the Heisenberg Group
2016
The purpose of this paper is to introduce and study some basic concepts of quantitative rectifiability in the first Heisenberg group $\mathbb{H}$. In particular, we aim to demonstrate that new phenomena arise compared to the Euclidean theory, founded by G. David and S. Semmes in the 90's. The theory in $\mathbb{H}$ has an apparent connection to certain nonlinear PDEs, which do not play a role with similar questions in $\mathbb{R}^{3}$. Our main object of study are the intrinsic Lipschitz graphs in $\mathbb{H}$, introduced by B. Franchi, R. Serapioni and F. Serra Cassano in 2006. We claim that these $3$-dimensional sets in $\mathbb{H}$, if any, deserve to be called quantitatively $3$-rectifi…
The Hajłasz Capacity Density Condition is Self-improving
2022
We prove a self-improvement property of a capacity density condition for a nonlocal Hajlasz gradient in complete geodesic spaces with a doubling measure. The proof relates the capacity density condition with boundary Poincare inequalities, adapts Keith-Zhong techniques for establishing local Hardy inequalities and applies Koskela-Zhong arguments for proving self-improvement properties of local Hardy inequalities. This leads to a characterization of the Hajlasz capacity density condition in terms of a strict upper bound on the upper Assouad codimension of the underlying set, which shows the self-improvement property of the Hajlasz capacity density condition. Open Access funding provided than…
Multi-marginal entropy-transport with repulsive cost
2020
In this paper we study theoretical properties of the entropy-transport functional with repulsive cost functions. We provide sufficient conditions for the existence of a minimizer in a class of metric spaces and prove the $\Gamma$-convergence of the entropy-transport functional to a multi-marginal optimal transport problem with a repulsive cost. We also prove the entropy-regularized version of the Kantorovich duality.
Assouad Type Dimensions in Geometric Analysis
2021
We consider applications of the dual pair of the (upper) Assouad dimension and the lower (Assouad) dimension in analysis. We relate these notions to other dimensional conditions such as a Hausdorff content density condition and an integrability condition for the distance function. The latter condition leads to a characterization of the Muckenhoupt Ap properties of distance functions in terms of the (upper) Assouad dimension. It is also possible to give natural formulations for the validity of Hardy–Sobolev inequalities using these dual Assouad dimensions, and this helps to understand the previously observed dual nature of certain cases of these inequalities. peerReviewed
On some partial data Calderón type problems with mixed boundary conditions
2021
In this article we consider the simultaneous recovery of bulk and boundary potentials in (degenerate) elliptic equations modelling (degenerate) conducting media with inaccessible boundaries. This connects local and nonlocal Calderón type problems. We prove two main results on these type of problems: On the one hand, we derive simultaneous bulk and boundary Runge approximation results. Building on these, we deduce uniqueness for localized bulk and boundary potentials. On the other hand, we construct a family of CGO solutions associated with the corresponding equations. These allow us to deduce uniqueness results for arbitrary bounded, not necessarily localized bulk and boundary potentials. T…
Un algoritmo PSO per l’ottimizzazione planimetrica dei tracciati stradali
2013
Questo studio propone un algoritmo di ricerca basato sulla tecnica di Intelligenza Artificiale di tipo Swarm (Particle Swarm Optimization - PSO) che consente di ottimizzare la geometria dei tracciati stradali, minimizzando una particolare funzione di costo che tiene conto di voci condizionanti la geometria del tracciato e di penalità relative ai vincoli presenti nel territorio. La pianificazione e la progettazione di un tracciato stradale costituiscono fasi intense di studio, fondamentali per garantire la sicurezza dell’infrastruttura. Definire un tracciato corretto, nel rispetto dei vincoli, può richiedere molto tempo e solo l’esperienza del Progettista e una approfondita analisi del terri…
Suite of Statistical Models Forecasting Latvian GDP
2014
Abstract We develop a suite of statistical models to forecast Latvian GDP. We employ various univariate and multivariate econometric techniques to obtain short-term GDP projections and to assess the performance of the models. We also comprise the information contained in components of GDP and obtain short-term GDP projections from disaggregated perspective. We run out-of-sample forecasting procedures to evaluate GDP projections and to assess forecasting accuracy of all individual statistical models. We conclude that factor and bridge models are among the best individually performing models in the suite. Forecasting accuracy obtained using disaggregated models of factor and bridge models is …
Estimating the safety performance function for urban unsignalized four-legged one-way intersections in Palermo, Italy
2014
Abstract Starting from consideration that urban intersections are sites with promise for safety and operational improvements, the paper describes the steps taken to develop a crash predictive model for estimating the safety performance of urban unsignalized intersections located in Palermo, Italy. The focus is on unsignalized four-legged one-way intersections widespread in Italian downtowns. The sample considered in the study consist of 92 intersections in Palermo, Italy. For the study were collected crashes occurred in the sites during the years 2006-2012, geometric design and functional characteristics and traffic flow. Results showed that data were overdispersed and NB1 distributed. In o…
A Gaschütz–Lubeseder Type Theorem in a Class of Locally Finite Groups
1999
The aim of this paper is to present a Gaschutz–Lubeseder type theorem in the class cL of all radical locally finite groups satisfying min−p for all primes p. Notice that these groups are countable and co-Hopfian by [1, (5.4.8)]. In retrospect, the theory of saturated formations of finite soluble groups began with the results of Gaschutz [3] in 1963. He introduced the concept of “covering subgroup” as a generalization of Sylow and Hall subgroups. These covering subgroups have many of the properties of Sylow and Hall subgroups other than the arithmetic ones. The main idea of Gaschutz’s work was concerned with group theoretical classes having the same properties. He defined a formation F to be…