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pro vyhledávání: '"D'ANDREA, FRANCESCO"'
Autor:
D'Andrea, Francesco
We study embeddings $E\to E\times E$ of a directed graph $E$ that induce a *-homomorphism $A\otimes A\to A$, where $A:=C^*(E)^{U(1)}$ is the core of the graph C*-algebra of $E$. Through the external product in K-theory, any such a *-homomorphism indu
Externí odkaz:
http://arxiv.org/abs/2410.06242
Autor:
Battaglia, Andrea Francesco, Krucker, Säm, Veronig, Astrid M., Stiefel, Muriel Zoë, Warmuth, Alexander, Benz, Arnold O., Ryan, Daniel F., Collier, Hannah, Harra, Louise
In general, large solar flares are more efficient at accelerating high-energy electrons than microflares. Nonetheless, we sometimes observe microflares that accelerate electrons to high energies. We statistically characterize 39 microflares with stri
Externí odkaz:
http://arxiv.org/abs/2409.14466
Autor:
D'Andrea, Francesco
Quantum spheres are among the most studied examples of compact quantum spaces, described by C*-algebras which are Cuntz-Krieger algebras of a directed graph, as proved by Hong and Szyma\'nski in 2002. About five years earlier, in 1997, Sheu proved th
Externí odkaz:
http://arxiv.org/abs/2407.02169
Autor:
D'Andrea, Francesco
For $n\in\mathbb{N}$ and $q\in [0,1[$, the Vaksman-Soibelman quantum sphere $S^{2n+1}_q$ is described by an associative algebra $\mathcal{A}(S^{2n+1}_q)$ deforming the algebra of polynomial functions on the 2n+1 dimensional unit sphere. Its C*-envelo
Externí odkaz:
http://arxiv.org/abs/2406.17288
Autor:
Li, Ying, Jing, Zhichen, Song, De-Chao, Li, Qiao, Tian, Jun, Liu, Xiaofeng, Wang, Ya, Ding, M. D., Battaglia, Andrea Francesco, Feng, Li, Li, Hui, Gan, Weiqun
The white-light continuum emissions in solar flares (i.e., white-light flares) are usually observed on the solar disk but, in a few cases, off the limb. Here we present on-disk as well as off-limb continuum emissions at 3600 {\AA} (in the Balmer cont
Externí odkaz:
http://arxiv.org/abs/2402.07374
Autor:
D'Andrea, Francesco
In this survey, we discuss the description of Vaksman-Soibelman quantum spheres using graph C*-algebras, following the seminal work of Hong and Szyma\'nski. We give a slightly different proof of the isomorphism with a graph C*-algebra, borrowing the
Externí odkaz:
http://arxiv.org/abs/2312.16481
Autor:
Saqri, Jonas, Veronig, Astrid M., Battaglia, Andrea Francesco, Dickson, Ewan C. M., Gary, Dale E., Krucker, Säm
We investigate two microflares of GOES classes A9 and C1 (after background subtraction) observed by STIX onboard Solar Orbiter with exceptionally strong nonthermal emission. We complement the hard X-ray imaging and spectral analysis by STIX with co-t
Externí odkaz:
http://arxiv.org/abs/2312.06856
Autor:
D'Andrea, Francesco
The aim of this book is to provide an elementary introduction, complete with detailed proofs, to the celebrated tilings of the plane discovered by Sir Roger Penrose in the `70s. The book covers many aspects of Penrose tilings, including the study of
Externí odkaz:
http://arxiv.org/abs/2310.18950
Autor:
Battaglia, Andrea Francesco, Hudson, Hugh, Warmuth, Alexander, Collier, Hannah, Jeffrey, Natasha L. S., Caspi, Amir, Dickson, Ewan C. M., Saqri, Jonas, Purkhart, Stefan, Veronig, Astrid M., Harra, Louise, Krucker, Säm
Publikováno v:
A&A 679, A139 (2023)
It is well known among the scientific community that solar flare activity often begins well before the main impulsive energy release. Our aim is to investigate the earliest phase of four distinct flares observed by Solar Orbiter/STIX and determine th
Externí odkaz:
http://arxiv.org/abs/2310.04234