Zum Zusammenhang zwischen Größe und Wachstum bei Gründungen - Empirische Ergebnisse für West-Deutschland

The present paper deals with the question whether 'Gibrat's law' is applicable to firms founded between 1989 and 1996 within the Western German manufacturing sector or not. The underlying assumption is that size of a firm has no in uence on its growth. Growth is rather determined by a process of random in uences. Within the context of the econometric analyses conducted in the present study, firms are subdivided into innovative and non-innovative young firms. A method introduced in Chesher (1979) is used to explore 'Gibrat's law' in order to examine the influence of firm size on growth. Moreover we test whether the growth process of firms remains stable over time or not. This so-called 'persistence of growth'-hypothesis implies that growth in one period has an impact on growth in the following period. Using data from the ZEW-Foundation Panel (West), 'Gibrat's law' is rejected for the group of innovative as well as for the group of non-innovative young firms in all periods examined. This confirms the results of a number of empirical studies over the last years, indicating that smaller firms have larger growth potential than larger ones. --Young Innovative Firms,New Technology-based Firms (NTBFs),Employment Growth,Gibrat's Law

Almost Flat Planar Diagrams

We continue our study of matrix models of dually weighted graphs. Among the attractive features of these models is the possibility to interpolate between ensembles of regular and random two-dimensional lattices, relevant for the study of the crossover from two-dimensional flat space to two-dimensional quantum gravity. We further develop the formalism of large $N$ character expansions. In particular, a general method for determining the large $N$ limit of a character is derived. This method, aside from being potentially useful for a far greater class of problems, allows us to exactly solve the matrix models of dually weighted graphs, reducing them to a well-posed Cauchy-Riemann problem. The power of the method is illustrated by explicitly solving a new model in which only positive curvature defects are permitted on the surface, an arbitrary amount of negative curvature being introduced at a single insertion.Comment: harvmac.tex and pictex.tex. Must be compiled "big". Diagrams are written directly into the text in pictex command

Full result for the three-loop static quark potential

The three-loop corrections to the potential of two heavy quarks are computed. Analytic results for the most complicated master integrals are presented.Comment: To appear in the proceedings of 9th International Symposium on Radiative Corrections (RADCOR 2009): Applications of Quantum Field Theory to Phenomenology, Ascona, Switzerland, 25-30 Oct 200