237,153 research outputs found
The Hubbard chain: Lieb-Wu equations and norm of the eigenfunctions
We argue that the square of the norm of the Hubbard wave function is
proportional to the determinant of a matrix, which is obtained by linearization
of the Lieb-Wu equations around a solution. This means that in the vicinity of
a solution the Lieb-Wu equations are non-degenerate, if the corresponding wave
function is non-zero. We further derive an action that generates the Lieb-Wu
equations and express our determinant formula for the square of the norm in
terms of the Hessian determinant of this action.Comment: 11 pages, Late
Extracting a shape function for a signal with intra-wave frequency modulation
In this paper, we consider signals with intra-wave frequency modulation. To
handle this kind of signals effectively, we generalize our data-driven
time-frequency analysis by using a shape function to describe the intra-wave
frequency modulation. The idea of using a shape function in time-frequency
analysis was first proposed by Wu. A shape function could be any periodic
function. Based on this model, we propose to solve an optimization problem to
extract the shape function. By exploring the fact that s is a periodic
function, we can identify certain low rank structure of the signal. This
structure enables us to extract the shape function from the signal. To test the
robustness of our method, we apply our method on several synthetic and real
signals. The results are very encouraging
Graph homomorphisms, the Tutte polynomial and “q-state Potts uniqueness”
We establish for which weighted graphs H homomorphism functions from multigraphs
G to H are specializations of the Tutte polynomial of G, answering a question
of Freedman, Lov´asz and Schrijver.
We introduce a new property of graphs called “q-state Potts uniqueness” and relate
it to chromatic and Tutte uniqueness, and also to “chromatic–flow uniqueness”,
recently studied by Duan, Wu and Yu.Ministerio de Educación y Ciencia MTM2005-08441-C02-0
Structural and optical properties of MOCVD AllnN epilayers
7] M.-Y. Ryu, C.Q. Chen, E. Kuokstis, J.W. Yang, G. Simin, M. Asif Khan, Appl. Phys. Lett. 80 (2002) 3730. [8] D. Xu, Y. Wang, H. Yang, L. Zheng, J. Li, L. Duan, R. Wu, Sci. China (a) 42 (1999) 517. [9] H. Hirayama, A. Kinoshita, A. Hirata, Y. Aoyagi, Phys. Stat. Sol. (a) 188 (2001) 83. [10] Y. Chen, T. Takeuchi, H. Amano, I. Akasaki, N. Yamada, Y. Kaneko, S.Y. Wang, Appl. Phys. Lett. 72 (1998) 710. [11] Ig-Hyeon Kim, Hyeong-Soo Park, Yong-Jo Park, Taeil Kim, Appl. Phys. Lett. 73 (1998) 1634. [12] K. Watanabe, J.R. Yang, S.Y. Huang, K. Inoke, J.T. Hsu, R.C. Tu, T. Yamazaki, N. Nakanishi, M. Shiojiri, Appl. Phys. Lett. 82 (2003) 718
Copyleft e maremoto
99 p.Libro ElectrónicoSe presentan diferentes artículos con casos relacionados con el derecho y acceso a la infornmación desde diferentes escenarios como lo son el derecho a la lectura, y los derechos de autor como lo son el copyright y el copyleftEl Derecho a la Lectura 9
Richard Stallman
Copyright y Maremoto 23
Wu Ming 1
El Copyleft explicado a los niños 35
Wu Ming 1
Copiar, robar, mandar 45
César Rendueles
El futuro digital y el pasado analógico 71
Kembrew McLeod
Glosario Básico 9
A Common Election Day for Euro Zone Member States?
This paper tests for the Euro zone the hypothesis put forward by Sapir and Sekkat (1999) that synchronizing elections might improve welfare. After identifying a political budget cycle in the Euro zone we build a politico-macroeconomic model and simulate the effects of adopting a common election day in the 12 Euro zone member states. The results support most of the theoretical predictions by Sapir-Sekkat: (i) Synchronizing the elections could enhance GDP growth, reduce unemployment, but leads to increased inflation and in some countries to a deterioration of the budget; higher inflation forces ECB to monetary restrictions. (ii) If the synchronization happens asymmetrically - either only in the large or only in the small Euro zone countries - the result depends on the size of the spillovers. (iii) As anticipated in Sapir -Sekkat a common election day is a further step towards the desired "European business cycle", however, at the cost of increasing its amplitude. Harmonizing elections is another method of policy coordination. Whether this leads to higher welfare is a matter of weighting the different macroeconomic outcomes and it also depends on the model applied. (author's abstract)Series: EI Working Papers / Europainstitu
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