Perfect single error-correcting codes in the Johnson Scheme

Delsarte conjectured in 1973 that there are no nontrivial pefect codes in the Johnson scheme. Etzion and Schwartz recently showed that perfect codes must be k-regular for large k, and used this to show that there are no perfect codes correcting single errors in J(n,w) for n <= 50000. In this paper we show that there are no perfect single error-correcting codes for n <= 2^250.Comment: 4 pages, revised, accepted for publication in IEEE Transactions on Information Theor

Transverse-Longitudinal Coupling by Space Charge in Cyclotrons

A method is presented that enables to compute the parameters of matched beams with space charge in cyclotrons with emphasis on the effect of the transverse-longitudinal coupling. Equations describing the transverse-longitudinal coupling and corresponding tune-shifts in first order are derived for the model of an azimuthally symmetric cyclotron. The eigenellipsoid of the beam is calculated and the transfer matrix is transformed into block-diagonal form. The influence of the slope of the phase curve on the transverse-longitudinal coupling is accounted for. The results are generalized and numerical procedures for the case of an AVF cyclotron are presented. The algorithm is applied to the PSI Injector II and Ring cyclotron and the results are compared to TRANSPORT.Comment: 8 pages, 2 figure

Design and Value: Spatial Form and the Economic Failure of a Mall

Real estate analysts have not had the tools to identify the functional problems of real estate because they have not focused on configuration. Space syntax is a way to represent, describe and evaluate spatial configurations or patterns created through building and urban design. Space syntax was used to systematically describe the configuration of a failed luxury shopping mall. Shape recognition techniques transform the plan into a mathematical network that can be analyzed. Network node parameters can be related to more traditional measures like occupancy and revenues by location. Thus revealed, the underlying spatial structure of the failed mall is compared to that of a similar but successful mall and its functional deficiencies identified.

No Place To Hide: The Global Crisis in Equity Markets in 2008/09

This paper provides a broad analysis of the effect of the current financial crisis on global equity markets and their major components. We also examine the magnitude of the crisis in terms of value destruction in comparison to other market crashes. In brief, upon looking at return performance across an array of regions, countries, and sectors, broad market averages are down approximately 40% on their end of 2006 levels. While deterioration started in most markets in early to mid 2008, the crisis period of mid September to the end of October 2008 is responsible for the lion's share of the collapse with just about all indices falling 30 - 40% in this short period. Financial sectors have taken a bigger hit than non-financials over the period, though they both suffered similarly during the peak of the crisis. Due to larger rises in 2007 the emerging markets drop more in 2008 than developed markets but in large part end up at the same level as the other markets. The global nature of the crisis is also apparent from the high correlations between markets and investment styles that further increased during the crisis. As a result, diversification provided little help to investors when needed most as markets dropped in tandem.Equity market, financial crisis, shareholder value, performance, international finance

The GL-l.u.st.\ constant and asymmetry of the Kalton-Peck twisted sum in finite dimensions

We prove that the Kalton-Peck twisted sum $Z_2^n$ of $n$-dimensional Hilbert spaces has GL-l.u.st.\ constant of order $\log n$ and bounded GL constant. This is the first concrete example which shows different explicit orders of growth in the GL and GL-l.u.st.\ constants. We discuss also the asymmetry constants of $Z_2^n$