Inflation with teleparallelism: Can torsion generate primordial fluctuations without local Lorentz symmetry?

Arbitrary generalization to the teleparallel equivalent of general relativity loses local Lorentz invariance to reparametrize the orthonormal coordinate system and gives rise to asymmetry field equations. We investigate consequences of local Lorentz violation to primordial fluctuations in extended single field inflationary models based on the scalar-tensor formulation of the torsion scalar $T$ that effectively includes $f(T)$ gravity as a special case. We show that despite some asymmetry part of the field equations are removed in a spatially homogeneous and isotropic cosmic background, no subhorizon scalar-perturbation mode can survive by the time of horizon crossing. As a result, any scalar field mediated in torsion cannot generate enough primordial density inhomogeneity alone, even if it brings some de Sitter background solutions in generalized teleparallel gravity.Comment: 6 pages, to be publishe

FAMILY OWNERSHIP AND CONTROL IN LARGE FIRMS: THE GOOD, THE BAD, THE IRRELEVANT -- AND WHY

There is a major debate regarding the role of concentrated family ownership and control in large firms, with three positions suggesting that such concentration is (1) good, (2) bad, or (3) irrelevant for firm performance. This article reports two studies to shed further light on this debate. Study 1 uses 744 publicly listed large firms in eight Asian countries to test competing hypotheses on the impact of the combination of family ownership and control on firm performance. On a country-by-country basis, our findings support all three positions. On an aggregate, pooled sample basis, the results support the “irrelevant” position. Study 2, based on a sample of 688 firms from the same eight Asian countries, endeavors to answer why Study 1 obtains different results for different countries. We theorize and document that Study 1 findings may be systematically associated with the level of shareholder protection embodied in legal and regulatory institutions. Study 2 thus sketches the contours of a cross-country, institution-based theory of corporate governance. Overall, our two studies lead to a finer-grained and more cumulative understanding of the crucial debate on family ownership and control in large firms.http://deepblue.lib.umich.edu/bitstream/2027.42/57220/1/wp840 .pd

Partial Strong Converse for the Non-Degraded Wiretap Channel

We prove the partial strong converse property for the discrete memoryless \emph{non-degraded} wiretap channel, for which we require the leakage to the eavesdropper to vanish but allow an asymptotic error probability $\epsilon \in [0,1)$ to the legitimate receiver. We show that when the transmission rate is above the secrecy capacity, the probability of correct decoding at the legitimate receiver decays to zero exponentially. Therefore, the maximum transmission rate is the same for $\epsilon \in [0,1)$, and the partial strong converse property holds. Our work is inspired by a recently developed technique based on information spectrum method and Chernoff-Cramer bound for evaluating the exponent of the probability of correct decoding