Search results for "Private communication"
showing 3 items of 3 documents
Revising the observable consequences of slow-roll inflation
2009
We study the generation of primordial perturbations in a (single-field) slow-roll inflationary Universe. In momentum space, these (Gaussian) perturbations are characterized by a zero mean and a nonzero variance Delta(2) (k, t). However, in position space the variance diverges in the ultraviolet. The requirement of a finite variance in position space forces one to regularize Delta(2) (k, t). This can (and should) be achieved by proper renormalization in an expanding Universe in a unique way. This affects the predicted scalar and tensorial power spectra (evaluated when the modes acquire classical properties) for wavelengths that today are at observable scales. As a consequence, the imprint of…
Countably compact weakly Whyburn spaces
2015
The weak Whyburn property is a generalization of the classical sequential property that was studied by many authors. A space X is weakly Whyburn if for every non-closed set \({A \subset X}\) there is a subset \({B \subset A}\) such that \({\overline{B} \setminus A}\) is a singleton. We prove that every countably compact Urysohn space of cardinality smaller than the continuum is weakly Whyburn and show that, consistently, the Urysohn assumption is essential. We also give conditions for a (countably compact) weakly Whyburn space to be pseudoradial and construct a countably compact weakly Whyburn non-pseudoradial regular space, which solves a question asked by Angelo Bella in private communica…
Siciliani al fronte. Lettere dalla Grande Guerra
2017
La Prima guerra mondiale è l'evento epocale che segna l'inizio del Novecento. Questo volume si pone l'obiettivo di indagare l'impatto del conflitto sulla Sicilia nell'ambito di una rinnovata linea di ricerca. Cento anni fa, nel 1917, dopo Caporetto, prese corpo una raccolta di lettere e altri testi di e su 23 militari siciliani, mai pubblicata e qui presentata in edizione critica e accompagnata da un'introduzione ed un saggio. Il libro dà conto di come la cosiddetta borghesia patriottica dell'isola visse e percepì l'inedita e sconvolgente esperienza bellica. The First World War is the epochal event that marks the beginning of the twentieth century. This volume aims to investigate the impact…