1,721,086 research outputs found
Central limit theorems for multicolor urns with dominated colors
Full text linkAn urn contains balls of d≥2 colors. At each time n≥1, a ball is drawn and then replaced together with a random number of balls of the same color. Let A n = diag (An,1,…,An,d) be the n-th reinforce matrix. Assuming that EAn,j=EAn,1 for all n and j, a few central limit theorems (CLTs) are available for such urns. In real problems, however, it is more reasonable to assume that EA n,j = EA n,1 whenever n ≥ 1 and 1 ≤ j ≤ d0 , liminfn EAn,1 > limsupn EAn,j whenever j > d0 for some integer 1≤d0≤d. Under this condition, the usual weak limit theorems may fail, but it is still possible to prove the CLTs for some slightly different random quantities. These random quantities are obtained by neglecting dominated colors, i.e., colors from d0+1 to d, and they allow the same inference on the urn structure. The sequence (An : n ≥ 1) is independent but need not be identically distributed. Some statistical applications are given as well
On coherent conditional probabilities and disintegrations
No full textExistence of coherent extensions of coherent conditional probabilities is one of the major merits of de Finetti's theory of probability. However, coherent extensions which meet some special property, like sigma-additivity or disintegrability, can fail to exist. An example is given where a coherent and sigma-additive conditional probability cannot be extended preserving both sigma-additivity and coherence. Motivated by such example, conditions are provided in order that a coherent and sigma-additive conditional probability admits a coherent and sigma-additive extension. Moreover, conditions are given for the existence of disintegrations, possibly sigma-additive, of a probability along a partition
Convergence in distribution of nonmeasurable random elements
Full text linkA notion of convergence in distribution for non (necessarily) measurable random elements, due to Hoffmann-Jorgensen, is characterized in terms of weak convergence of finitely additive probability measures. A similar characterization is given for a strengthened version of such a notion. Further, it is shown that the empirical process for an exchangeable sequence can fail to converge, due to the nonexistence of any measurable limit, although it converges for an i.i.d. sequence. Because of phenomena of this type, Hoffmann-Jorgensen's definition is extended to the case of a nonmeasurable limit. In the extended definition, naturally suggested by the main results, the limit is a finitely additive probability measure
Riflession e proposte per un modello di polizza assicurativa per la copertura della responsabilità civile nel settore dell'Endoscopia
No full textGli autori, alla luce di considerazioni sulla responsabilità civile in Endoscopia Digetsiva, propongono un modello di contratto assicurativo ad alto contenuto "tecnico" per la tutela dei professionist
Indagine comparativa in ordine alla prassi del consenso informato. Risultati di un'inchiesta internazionale svolta tramite questionari inviati alle società scientifiche
No full textGli autori riferiscono di una inchiesta svolta in campo internazionale sulla prassi del consenso informato, attraverso la somministrazione di un questionario distribuito tramite le società scientifiche di Endoscopia Digestiv
Nickel(0) complexes with the hybrid bidentate ligand 1-(thioethyl)-2-(diphenylphosphino)ethane. Synthesis and catalytic properties of the related nickel hydride derivative
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