154 research outputs found
Relativistic MOND as an alternative to the dark matter paradigm
Milgrom's Modified Newtonian dynamics (MOND) provides an efficient way to
summarize phenomenology of galaxies which does not lean on the notion of dark
matter; it has great predictive power. Here I briefly review MOND as well as
its implementation as a nonrelativistic modified gravity theory, AQUAL.
Gravitational lensing and cosmology call for a relativistic gravity theory
different from general relativity if dark matter is to be avoided. In recent
years such a theory, TVS, has emerged from the marriage of AQUAL with the
timelike vector field of Sanders. I discuss its structure and some of its
successes and shortcomings.Comment: Invited talk presented at the International Conference on Particles
and Nuclei (PANIC08), Eilat, Israel, November 9-14, 2008. To appear in
Nuclear Physics A. 6 pages LaTe
The Relation between Physical and Gravitational Geometry
The appearance of two geometries in one and the same gravitational theory is
familiar. Usually, as in the Brans-Dicke theory or in string theory, these are
conformally related Riemannian geometries. Is this the most general relation
between the two geometries allowed by physics ? We study this question by
supposing that the physical geometry on which matter dynamics take place could
be Finslerian rather than just Riemannian. An appeal to the weak equivalence
principle and causality then leads us the conclusion that the Finsler geometry
has to reduce to a Riemann geometry whose metric - the physical metric - is
related to the gravitational metric by a generalization of the conformal
transformation.Comment: 15 pages, Te
The theory of the firm and its critics: a stocktaking and assessment
Includes bibliographical references."Prepared for Jean-Michel Glachant and Eric Brousseau, eds. New Institutional Economics: A Textbook, Cambridge, Cambridge University Press.""This version: August 22, 2005."Since its emergence in the 1970s the modern economic or Coasian theory of the
firm has been discussed and challenged by sociologists, heterodox economists, management
scholars, and other critics. This chapter reviews and assesses these critiques, focusing on behavioral
issues (bounded rationality and motivation), process (including path dependence and the selection argument), entrepreneurship, and the challenge from knowledge-based
theories of the firm
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