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302 results on '"Ferri, Fabio"'

1. On the number of quaternion and dihedral braces and Hopf--Galois structures

Author

Byott, Nigel P. and Ferri, Fabio

Subjects
Mathematics - Rings and Algebras, Mathematics - Group Theory, Mathematics - Number Theory, 20N99 (Primary) 16T05, 12F10, 16T25 (Secondary)
Abstract

We prove a conjecture of Guarnieri and Vendramin on the number of braces of a given order whose multiplicative group is a generalised quaternion group. At the same time, we give a similar result where the multiplicative group is dihedral. We also enumerate Hopf-Galois structures of abelian type on Galois extensions with generalised quaternion or dihedral Galois group., Comment: 25 pages. Additional references included

Published
2024

2. Applications of representation theory and of explicit units to Leopoldt's conjecture

Author

Ferri, Fabio and Johnston, Henri

Subjects
Mathematics - Number Theory, 11R23 (Primary) 11R27, 19A22, 20C15 (Secondary)
Abstract

Let $L/K$ be a Galois extension of number fields and let $G=\mathrm{Gal}(L/K)$. We show that under certain hypotheses on $G$, for a fixed prime number $p$, Leopoldt's conjecture at $p$ for certain proper intermediate fields of $L/K$ implies Leopoldt's conjecture at $p$ for $L$. We also obtain relations between the Leopoldt defects of intermediate extensions of $L/K$. By applying a result of Buchmann and Sands together with an explicit description of units and a special case of the above results, we show that given any finite set of prime numbers $\mathcal{P}$, there exists an infinite family $\mathcal{F}$ of totally real $S_{3}$-extensions of $\mathbb{Q}$ such that Leopoldt's conjecture for $F$ at $p$ holds for every $F \in \mathcal{F}$ and $p \in \mathcal{P}$., Comment: 23 pages; preliminary version; comments welcome

Published
2023

3. Leopoldt-type theorems for non-abelian extensions of Q

Author

Ferri, Fabio

Subjects
Mathematics - Number Theory
Abstract

We prove new results concerning the additive Galois module structure of certain wildly ramified finite non-abelian extensions of Q. In particular, when K/Q is a Galois extension with Galois group G isomorphic to A4, S4 or A5, we give necessary and sufficient conditions for the ring of integers of K to be free over its associated order in the rational group algebra Q[G]., Comment: 30 pages

Published
2021

4. Applications of representation theory and K-theory to problems in algebraic number theory

Author

Ferri, Fabio and Johnston, Henri

Subjects
number theory, algebraic number theory, representation theory, Galois theory, K-theory
Abstract

In this thesis we consider three main problems: the Galois module structure of rings of integers in wildly ramified extensions of Q; Leopoldt's conjecture; and non-commutative Fitting ideals and the non-abelian Brumer-Stark conjecture. For each of these problems, which correspond to each main chapter, we will review and use tools from representation theory and algebraic K-theory. In the first main chapter, we will prove new results concerning the additive Galois module structure of certain wildly ramified finite non-abelian extensions of Q. In particular, when K/Q is a Galois extension with Galois group G isomorphic to A4, S4 or A5, we give necessary and sufficient conditions for the ring of integers OK to be free over its associated order in the rational group algebra Q[G]. In the second main chapter, we will work on Leopoldt's conjecture. Let p be a rational prime and let L/K be a Galois extension of number fields with Galois group G. Under certain hypotheses, we show that Leopoldt's conjecture at p for certain proper intermediate fields of L/K implies Leopoldt's conjecture at p for L; a crucial tool will be the theory of norm relations in Q[G]. We also consider relations between the Leopoldt defects at p of intermediate extensions of L/K. Finally, we will investigate new properties of (non-commutative) Fitting ideals in integral group rings, with the general idea of reducing to simpler abstract groups (such as abelian groups) that can emerge as subquotients. As an application we will provide a direct proof of the (non-abelian) Brumer-Stark conjecture in certain cases, by reducing to the abelian case as recently proved by Dasgupta and Kakde. The direct approach avoids use of technical machinery such as the equivariant Tamagawa number conjecture.

Published
2022

5. How far is an extension of $p$-adic fields from having a normal integral basis?

Author

Del Corso, Ilaria, Ferri, Fabio, and Lombardo, Davide

Subjects
Mathematics - Number Theory
Abstract

Let $L/K$ be a finite Galois extension of $p$-adic fields with group $G$. It is well-known that $\mathcal{O}_L$ contains a free $\mathcal{O}_K[G]$-submodule of finite index. We study the minimal index of such a free submodule, and determine it exactly in several cases, including for any cyclic extension of degree $p$ of $p$-adic fields., Comment: 31 pages. v2: minor typos corrected (a factor 1/2 was missing in the statement of Proposition 3.5), results unchanged

Published
2020

6. Tame Galois module structure revisited

Author

Ferri, Fabio and Greither, Cornelius

Subjects
Mathematics - Number Theory
Abstract

A number field $K$ is Hilbert-Speiser if all of its tame abelian extensions $L/K$ admit NIB (normal integral basis). It is known that $\mathbb{Q}$ is the only such field, but when we restrict $\text{Gal}(L/K)$ to be a given group $G$, the classification of $G$-Hilbert-Speiser fields is far from complete. In this paper, we present new results on so-called $G$-Leopoldt fields. In their definition, NIB is replaced by ``weak NIB'' (defined below). Most of our results are negative, in the sense that they strongly limit the class of $G$-Leopoldt fields for some particular groups $G$, sometimes even leading to an exhaustive list of such fields or at least to a finiteness result. In particular we are able to correct a small oversight in a recent article by Ichimura concerning Hilbert-Speiser fields., Comment: 16 pages. Same version as the published paper

Published
2018

14. Experimental evidence of high-resolution ghost imaging and ghost diffraction with classical thermal light

Author

Magatti, Davide, Ferri, Fabio, Gatti, Alessandra, Bache, Morten, Brambilla, Enrico, and Lugiato, Luigi A.

Subjects
Quantum Physics
Abstract

High-resolution ghost image and ghost diffraction experiments are performed by using a single source of thermal-like speckle light divided by a beam splitter. Passing from the image to the diffraction result solely relies on changing the optical setup in the reference arm, while leaving untouched the object arm. The product of spatial resolutions of the ghost image and ghost diffraction experiments is shown to overcome a limit which was formerly thought to be achievable only with entangled photons., Comment: 5 pages, 4 figures

Published
2004
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16. Melt Inclusions in Arclogitic Xenoliths Constrain the Genesis of the Lower Continental Arc Crust beneath the Northern Volcanic Zone, Colombia

Author

Gianola, Omar, primary, Costa, Benedetta, additional, Ferri, Fabio, additional, Gilio, Mattia, additional, Petrelli, Maurizio, additional, Murri, Mara, additional, Barbaro, Anna, additional, Alvaro, Matteo, additional, Rodríguez-Vargas, Andrés, additional, Poli, Stefano, additional, and Cesare, Bernardo, additional

Published
2023
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22. Trattamento automatico della lingua a supporto dell’editoria: primi esperimenti con il Devoto-Oli Junior

Author

Dini, Irene, Dell’Orletta, Felice, Ferri, Fabio, Gismondi, Biancamaria, and Montemagni, Simonetta

Subjects
Computational Linguistics, linguistica, linguistique computationelle, Linguistics, linguistica computazionale, linguistique, Language
Abstract

The paper illustrates the results of a first experiment in which Natural Language Processing was used to support the revision of a children’s dictionary, in particular for what concerns style and wording of definitions and the enrichment of the list of lemmas. The results achieved are promising and demonstrate the potential of a synergy to be strengthened in the publishing sector. L’articolo illustra i risultati di un esperimento all’interno del quale tecnologie di TAL sono state utilizzate a supporto della redazione di un dizionario per bambini, in particolare per quanto riguarda la formulazione delle definizioni e l’aggiornamento del lemmario. I risultati raggiunti sono promettenti e mostrano il potenziale di una sinergia da rafforzare nel settore dell’Editoria.

Published
2022

23. Proceedings of the Eighth Italian Conference on Computational Linguistics CliC-it 2021

Author

Achena, Flavia, Aggarwal, Akshay, Albanesi, Davide, Albertin, Giorgia, Alzetta, Chiara, Anselma, Luca, Aparaschivei, Lavinia, Archetti, Francesco, Barattieri di San Pietro, Chiara, Barrón-Cedeño, Alberto, Basile, Pierpaolo, Basile, Valerio, Basili, Roberto, Bellandi, Andrea, Bosco, Cristina, Bosque-Gil, Julia, Brunato, Dominique, Brutti, Alessio, Budeanu, Ancuta, Cabrio, Elena, Canazza, Sergio, Candelieri, Antonio, Caselli, Tommaso, Casola, Silvia, Cassotti, Pierluigi, Cattoni, Roldano, Cecchini, Flavio Massimiliano, Celli, Fabio, Cerulli, Aldo, Cettolo, Mauro, Chesi, Cristiano, Cignarella, Alessandra Teresa, Cimiano, Philipp, Cimino, Andrea, Colella, Annalisa, Croce, Danilo, Cutugno, Francesco, Dall’Acqua, Anna, Dangelo, Paolo, Dei Rossi, Stefano, Dell’Orletta, Felice, Demartini, Silvia, De Gemmis, Marco, De Mattei, Lorenzo, Dini, Irene, Di Bratto, Martina, di Buono, Maria Pia, Di Caro, Luigi, Di Liello, Luca, Di Maro, Maria, Dufaux, Alain, Duzha, Armend, Elahi, Mohammad Fazleh, Ell, Basil, Ernandes, Marco, Fabrizi, Samuel, Fallucchi, Francesca, Fantoli, Margherita, Fernández, Raquel, Ferrari, Pier Luigi, Ferrero, Dario, Ferri, Fabio, Fersini, Elisabetta, Florio, Komal, Flouris, Giorgos, Frenda, Simona, Frey, Jennifer-Carmen, Gattero, Valerio, Gemelli, Sara, Gemmis, Marco de, Giovannetti, Emiliano, Gismondi, Biancamaria, Grasso, Francesca, Grotto, Francesco, Iacono, Maria, Iovine, Andrea, Jansen, Lennert, Jezek, Elisabetta, Kaplan, Frédéric, Labruna, Tiziano, Lai, Mirko, Lavelli, Alberto, Lenci, Alessandro, Litta, Eleonora, Lombardi, Agnese, Lops, Pasquale, Louvan, Samuel, Luzietti, Roberta Bianca, Maffia, Marta, Magnini, Bernardo, Mahed Mousavi, Seyed, Mambrini, Francesco, Marchi, Simone, Marelli, Marco, Marra, Andrea, Martino, Maria De, Marziano, Giuseppe, Masini, Francesca, Mastromattei, Michele, Mattiola, Simone, Mazzei, Alessandro, Messina, Enza, Miaschi, Alessio, Minnema, Gosse, Montemagni, Simonetta, Moretti, Giovanni, Moschitti, Alessandro, Negri, Matteo, Negro, Roberto, Nicolas, Lionel, Nissim, Malvina, Nolano, Gennaro, Ògúnrẹ̀mí, Tolúlọpẹ, Onorati, Dario, Origlia, Antonio, Orrico, Riccardo, Paccosi, Teresa, Palmero Aprosio, Alessio, Papadakos, Panagiotis, Papantoniou, Katerina, Papi, Sara, Papini, Mafalda, Passaro, Lucia C., Passarotti, Marco, Patti, Viviana, Pezzelle, Sandro, Plank, Barbara, Plexousakis, Dimitris, Pretto, Niccolò, Puccinelli, Daniele, Ranaldi, Leonardo, Ravelli, Andrea Amelio, Reverberi, Carlo, Riccardi, Giuseppe, Rocchietti, Guido, Romani, Emma, Rosato, Luca, Rossi, Laura, Roth, Dan, Ruffolo, Paolo, Ruzzetti, Elena Sofia, Sabri, Nazanin, Salaris, Sara, Sanguinetti, Manuela, Schettino, Loredana, Schmalz, Veronica Juliana, Sciolette, Flavia, Semeraro, Giovanni, Siciliani, Lucia, Simi, Maria, Sinclair, Arabella, Sprugnoli, Rachele, Stemle, Egon W., Stranisci, Marco Antonio, Tamburini, Fabio, Terragni, Silvia, Tesei, Andrea, Tonelli, Sara, Tripodi, Rocco, Turchi, Marco, Uryupina, Olga, van der Goot, Margot J., Ventura, Viviana, Venturi, Giulia, Villata, Serena, Vorakitphan, Vorakit, Zanchi, Chiara, Zanzotto, Fabio Massimo, Zeman, Daniel, Zugarini, Andrea, Fersini, Elisabetta, Passarotti, Marco, and Patti, Viviana

Subjects
Computational Linguistics, linguistica, linguistique computationelle, Linguistics, LAN009000, CF, linguistica computazionale, linguistique, Language
Abstract

The eighth edition of the Italian Conference on Computational Linguistics (CLiC-it 2021) was held at Università degli Studi di Milano-Bicocca from 26th to 28th January 2022. After the edition of 2020, which was held in fully virtual mode due to the health emergency related to Covid-19, CLiC-it 2021 represented the first moment for the Italian research community of Computational Linguistics to meet in person after more than one year of full/partial lockdown.

Published
2022

24. List of Contributors

Author

Alessio, Priscila, primary, Aliaga, Alvaro E., additional, Aoki, Pedro H.B., additional, Craievich, Aldo F., additional, de Assumpção Pereira-da-Silva, Marcelo, additional, de Lima Leite, Fábio, additional, de Oliveira Neto, Mario, additional, Deda, Daiana K., additional, Ferreira, Marystela, additional, Ferri, Fabio A., additional, Furini, Leonardo N., additional, Garcia, Pâmela S., additional, Kellermann, Guinther, additional, Lamas, Diego G., additional, Leopoldo Constantino, Carlos J., additional, Miyazaki, Celina M., additional, Ramos, Ana P., additional, Shimizu, Flávio M., additional, Tararam, Ronald, additional, and Varela, José A., additional

Published
2017
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27. The CANOVA Study Real-World Evidence of Biologic Treatments in Moderate-Severe Psoriasis in Italy: A Gender Perspective

Author

Colombo, Delia, primary, Bianchi, Luca, additional, Fabbrocini, Gabriella, additional, Corrao, Salvatore, additional, Offidani, Annamaria, additional, Stingeni, Luca, additional, Costanzo, Antonio, additional, Pellacani, Giovanni, additional, Peris, Ketty, additional, Bardazzi, Federico, additional, Argenziano, Giuseppe, additional, Ruffolo, Silvana, additional, Dapavo, Paolo, additional, Carrera, Carlo, additional, Fargnoli, Maria Concetta, additional, Parodi, Aurora, additional, Romanelli, Marco, additional, Malagoli, Piergiorgio, additional, Zullo, Alessandro, additional, Ferri, Fabio, additional, Fiocchi, Martina, additional, and Zagni, Emanuela, additional

Published
2022
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29. Le disposizioni sui comuni per il 2021: una rassegna normativa nella fase di ripresa del Paese

Author

Romano Astolfo, Danilo Ballanti, Barbara Becchi, Gioacchino Benfante, Chiara Bergonzini, Paolo Brambilla, Valeria Bucci, Noemi Ilaria Buonsante, Rebeca C. Cabrera Rivera, Stefano Campostrini, Natalina Teresa Capua, Giovanna Colombini, Giovanni Carrosio, Elisa Cavasino, Fausto Corradin, Filippo Corradini, Michele Costola, Marzia De Donno, Silvia Degli Angeli, Marcello Degni, Elena di Carpegna Brivio, Cristina Equizzi, Giancarlo Ferrara, Andrea Ferri, Fabio Fiorillo, Giaime Gabrielli, Giampiero Maria Gallo, Elena Giovannini, Carla Golfieri, Raffaele Lagravinese, Eleonora Luciani, Chiara Mancini, Vanessa Manzetti, Silvia Martini, Marco Mastracci, Manuela Lucia Mei, Edoardo Meneghelli, Pasquale Mennuti, Elvina Merkaj, Larysa Minzyuk, Francesco Monaco, Andrea Morgia, Riccardo Mussari, Emanuele Padovani, Massimo Paradiso, Francesco Porcelli, Stefania Porchia, Stefano Pozzoli, Cristina Randi, Paolo Ravaioli, Giuliano Resce, Alberto Scheda, Giulia Valeria Sonzogno, Stefano Sotgiu, Marco Stradiotto, Elena Torri, Claudia Tubertini, Cesare Vignocchi, Flaviano Zandonai, Maristella Zantedeschi., Degni, M, Luciani, E, Luciani, E., Romano Astolfo, Danilo Ballanti, Barbara Becchi, Gioacchino Benfante, Chiara Bergonzini, Paolo Brambilla, Valeria Bucci, Noemi Ilaria Buonsante, Rebeca C. Cabrera Rivera, Stefano Campostrini, Natalina Teresa Capua, Giovanna Colombini, Giovanni Carrosio, Elisa Cavasino, Fausto Corradin, Filippo Corradini, Michele Costola, Marzia De Donno, Silvia Degli Angeli, Marcello Degni, Elena di Carpegna Brivio, Cristina Equizzi, Giancarlo Ferrara, Andrea Ferri, Fabio Fiorillo, Giaime Gabrielli, Giampiero Maria Gallo, Elena Giovannini, Carla Golfieri, Raffaele Lagravinese, Eleonora Luciani, Chiara Mancini, Vanessa Manzetti, Silvia Martini, Marco Mastracci, Manuela Lucia Mei, Edoardo Meneghelli, Pasquale Mennuti, Elvina Merkaj, Larysa Minzyuk, Francesco Monaco, Andrea Morgia, Riccardo Mussari, Emanuele Padovani, Massimo Paradiso, Francesco Porcelli, Stefania Porchia, Stefano Pozzoli, Cristina Randi, Paolo Ravaioli, Giuliano Resce, Alberto Scheda, Giulia Valeria Sonzogno, Stefano Sotgiu, Marco Stradiotto, Elena Torri, Claudia Tubertini, Cesare Vignocchi, Flaviano Zandonai, Maristella Zantedeschi., Degni, M, Luciani, E, and Luciani, E.

Published
2022

33. Size Segregation and Atomic Structural Coherence in Spontaneous Assemblies of Colloidal Cesium Lead Halide Nanocrystals

Author

Bertolotti, Federica, primary, Vivani, Anna, additional, Ferri, Fabio, additional, Anzini, Pietro, additional, Cervellino, Antonio, additional, Bodnarchuk, Maryna I., additional, Nedelcu, Georgian, additional, Bernasconi, Caterina, additional, Kovalenko, Maksym V., additional, Masciocchi, Norberto, additional, and Guagliardi, Antonietta, additional

Published
2022
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36. Recipes for diffuse correlation spectroscopy instrument design using commonly utilized hardware based on targets for signal-to-noise ratio and precision

Author

Cortese, Lorenzo, primary, Lo Presti, Giuseppe, additional, Pagliazzi, Marco, additional, Contini, Davide, additional, Dalla Mora, Alberto, additional, Dehghani, Hamid, additional, Ferri, Fabio, additional, Fischer, Jonas B., additional, Giovannella, Martina, additional, Martelli, Fabrizio, additional, Weigel, Udo M., additional, Wojtkiewicz, Stanislaw, additional, Zanoletti, Marta, additional, and Durduran, Turgut, additional

Published
2021
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37. Effectiveness and Safety of Ixazomib-Based Therapy in Relapsed/Refractory Multiple Myeloma (RRMM) Patients (Pts) Treated Outside the Clinical Trial Setting Via an Early Access Program (EAP) in Europe: Second Interim Analysis of the ‘Use Via Early Access to Ixazomib’ (UVEA-IXA) Study

Author

Ludwig, Heinz, Terpos, Evangelos, Mateos, María-Victoria, Boccadoro, Mario, Kishore, Bhuvan, Ramasamy, Karthik, Fernandez, Sylvie, Ferri, Fabio, Bent-Ennakhil, Nawal, Zomas, Athanasios, Gavini, François, and Hajek, Roman

Published
2020
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38. Optimization of diffuse correlation spectroscopy instrumental and experimental parameters based on precision targets

Author

Cortese, Lorenzo, primary, Lo Presti, Giuseppe, additional, Pagliazzi, Marco, additional, Fischer, Jonas B., additional, Giovannella, Martina, additional, Zanoletti, Marta, additional, Ferri, Fabio, additional, Martelli, Fabrizio, additional, Dalla Mora, Alberto, additional, Contini, Davide, additional, Wojtkiewicz, Stanislaw, additional, Dehghani, Hamid, additional, Weigel, Udo M., additional, and Durduran, Turgut, additional

Published
2021
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42. Anatectic melt inclusions in ultra high temperature granulites

Author

Gianola, Omar, primary, Bartoli, Omar, additional, Ferri, Fabio, additional, Galli, Andrea, additional, Ferrero, Silvio, additional, Capizzi, Luca S., additional, Liebske, Christian, additional, Remusat, Laurent, additional, Poli, Stefano, additional, and Cesare, Bernardo, additional

Published
2020
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48. Inversion of low-angle elastic light-scattering data with a new method devised by modification of the Chahine algorithm

Author

Ferri, Fabio, Righini, Gabriella, and Paganini, Enrico

Subjects
Light scattering -- Research, Astronomy, Physics
Abstract

A new inversion method, devised by modification of the nonlinear iterative method originally proposed by Chahine [J. Opt. Soc. Am. 58, 1634 (1968)] is applied to the inversion of low-angle elastic light-scattering data. The algorithm was tested by computer simulations carried out within the wave-vector range 2.5 x [10.sup.2]-2.5 x [10.sup.4] [cm.sup.-1]. The particle-size distributions were recovered in the 0.70-77-[[micro]meter] range of radii. Compared with the original method of Chahine, this algorithm is much more stable and reliable with respect to random noise, improves the overall reliability of the fitting, and allows both number and weight particle-size distributions to be retrieved accurately. When the performances of the method are investigated with respect to the noise, the results of the simulations show that the particle-size distributions can be recovered accurately up to noise levels of several rms percent. Key words: Particle sizing, inversion algorithm, elastic light scattering.

Published
1997

49. Commercial spectrophotometer for particle sizing

Author

Ferri, Fabio, Bassini, Alessandra, and Paganini, Enrico

Subjects
Spectrophotometer -- Usage, Particles -- Optical properties, Astronomy, Physics
Abstract

Particle-size distribution and the concentration of polystyrene particles suspended in water were accurately recovered from the inversion of spectral extinction data measured with a commercial spectrophotometer. The instrument was modified by placing a spatial filter in the collection optics to prevent low-angle scattered light from affecting the measurement of transmitted power. The data were inverted by use of a nonlinear iterative algorithm. When the extinction coefficient is measured in the k range of 0.3-1.1 [[micro]meter], the particle distributions can be retrieved over a diameter range of 0.6-2.8 [[micro]meter] for a wide interval of sample concentrations. The average diameters are recovered with a precision of better than [+ or -]1% and with accuracies consistent with the uncertainties by which the nominal diameters are known. The relative standard deviations of distributions corresponding to monodisperse samples are [+ or -]5-10%, whereas the accuracy on the measured concentrations is [approximately]5%. Key words: Particle sizing, inversion algorithm, spectral extinction.

Published
1997

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