A test for complementarities among multiple technologies that avoids the curse of dimensionality

We propose a strategy to identify the complementarity or substitutability among technology bundles. Under the assumption that alternative technologies are independent, we develop a hypothetical distribution of multiple technology adoptions. Differences between the observed distribution of technology choices and the hypothetical distribution can be subjected to statistical tests. Combinations of technologies that occur with greater frequency than would occur under independence are complementary technologies. Combinations that occur with less frequency are substitute technologies. This method is easily applied to simultaneous decisions regarding many technologies. We use the strategy to evaluate multiple technology adoptions on U.S. hog farms. We find that some technologies used in pork production are substitutable for one another while others are complementary. However, as the number of bundled technologies increases, they are increasingly likely to be complementary with one another, even if subsets are substitutes when viewed in isolation. This finding suggests that farmers have an incentive to adopt many technologies at once. Larger farms and farms run by more educated operators are the most likely to adopt multiple technologies. The complementarity among technologies in large bundles is contributing to a form of returns to scale that contributes to growth in average farm size.human capital; technology; adoption; complementarity; substitutability; independence; hogs; pork; farm size

Towards a Neo-Copenhagen Interpretation of Quantum Mechanics

The Copenhagen interpretation is critically considered. A number of ambiguities, inconsistencies and confusions are discussed. It is argued that it is possible to purge the interpretation so as to obtain a consistent and reasonable way to interpret the mathematical formalism of quantum mechanics, which is in agreement with the way this theory is dealt with in experimental practice. In particular, the essential role attributed by the Copenhagen interpretation to measurement is acknowledged. For this reason it is proposed to refer to it as a neo-Copenhagen interpretation

Non-Market Interactions

A large body of recent research argues that social, or non-market, interactions can explain a wide range of puzzling phenomena from fashion cycles to stock market crashes. This paper attempts to connect the range of these papers with a general model and a broad empirical overview. We establish conditions for existence and uniqueness of equilibria in social interactions models. The existence of multiple equilibria requires sufficient non-linearity in social interactions and only moderate heterogeneity across agents--strategic complementarities are neither necessary nor sufficient for multiple equilibria. We establish conditions for the existence of a social multiplier, which is the ratio of the aggregate outcome-input relationship to the individual outcome-input relationship. Models with multiple equilibria are empirically indistinguishable from models with significant social multipliers. Finally, we show the formal relationship between three known methods of empirically estimating social interactions, and suggests the plusses and minuses of these three approaches.

Institutions and Development Processes: the Role of Strategic Complementarities. A Review of main Literature

This survey is an overview on the literature that investigates the relationship between the institutions and development processes. The attention it has been focus, in sequence, on the ways in which it has been performed the empirical and the theoretical analysis of the relationship between the economic development and the role of institutions. As it is clear the first difficulty is the definition of what an institution is, so the survey gives dig relevance to the different manners to conceptualize the notion of institution. Another difficulty arises from the perplexity about how the efficiency of the institutions can be evaluated. This problem is related to the necessity to close off in the right way the weight and the influence of the institutions respect to the other variables on the economic development. The analysis of the complementarities involved in the development processes, can be a useful way to explain some kinds of relationship between institutions and development processes especially in the short run. The use of more elaborated indices to measure the in�uence of institutions in the economic system and of the coentegration models can improve the reliability of the empirical analysis. In the same manner the supermodularity and the supermodular games can efficiently explain the mechanism of the strategic complementarity between di¤erent kinds of institution generating virtuous development processes from a theoretical point of view. Necessarily, in the future, both the analysis must be integrated but, for the time being, the state of art in the two approaches represent a very good starting point for new outcomes related to the investigation on these type of kind of economic phenomena.Institutions, Complementarities, Development Process

The mystery of relationship of mechanics and field in the many-body quantum world

We have revealed three fatal errors incurred from a blind transferring of quantum field methods into the quantum mechanics. This had tragic consequences because it produced crippled model Hamiltonians, unfortunately considered sufficient for a description of solids including superconductors. From there, of course, Fr\"ohlich derived wrong effective Hamiltonian, from which incorrect BCS theory arose. 1) Mechanical and field patterns cannot be mixed. Instead of field methods applied to the mechanical Born-Oppenheimer approximation we have entirely to avoid it and construct an independent and standalone field pattern. This leads to a new form of the Bohr's complementarity on the level of composite systems. 2) We have correctly to deal with the center of gravity, which is under the field pattern "materialized" in the form of new quasipartiles - rotons and translons. This leads to a new type of relativity of internal and external degrees of freedom and one-particle way of bypassing degeneracies (gap formation). 3) The possible symmetry cannot be apriori loaded but has to be aposteriori obtained as a solution of field equations, formulated in a general form without translational or any other symmetry. This leads to an utterly revised view of symmetry breaking in non-adiabatic systems, namely Jahn-Teller effect and superconductivity. These two phenomena are synonyms and share a unique symmetry breaking.Comment: 24 pages, 9 sections; remake of abstract, introduction and conclusion; more physics, less philosoph