Perfect Competition

In his 1987 entry on ‘Perfect Competition’ in The New Palgrave, the author reviewed the question of the perfectness of perfect competition, and gave four alternative formalisations rooted in the so-called Arrow-Debreu-Mckenzie model. That entry is now updated for the second edition to include work done on the subject during the last twenty years. A fresh assessment of this literature is offered, one that emphasises the independence assumption whereby individual agents are not related except through the price system. And it highlights a ‘linguistic turn’ whereby Hayek’s two fundamental papers on ‘division of knowledge’ are seen to have devastating consequences for this research programme.Allocation of Resources; Perfect Competition; Exchange Economy

The Harris-Todaro Hypothesis

The Harris-Todaro hypothesis replaces the equality of wages by the equality of ‘expected’ wages as the basic equilibrium condition in a segmented but homogeneous labour market, and in so doing it generates an equilibrium level of urban unemployment when a mechanism for the determination of urban wages is specified. This article reviews work in which the Harris-Todaro hypothesis is embedded in canonical models of trade theory in order to investigate a variety of issues in development economics. These include the desirability (or the lack thereof) of foreign investment, the complications of an informal sector, and the presence of clearly identifiable ethnic groups.Harris-Todaro; Wages; Labour Economics; Labour Market; Rural to Urban Migration

BB and BcB_c mesons with NRQCD and Clover actions

We present preliminary results from our study of the heavy-light spectrum and decay constants. For the heavy quark, we use NRQCD at various masses around and above the $b$ quark mass. For the first time, the heavy quark action and the heavy-light current consistently include corrections at second order in the non-relativistic expansion, as well as the leading finite $a$ corrections. The light quarks are simulated using a tadpole-improved Clover action at various masses in the strange and $c$ quark region.Comment: 6 Pages LaTex. Axis files of figures included. Joint writeup of two talks presented at LATTICE96(heavy quarks

An Automated Algorithm for Approximation of Temporal Video Data Using Linear B'EZIER Fitting

This paper presents an efficient method for approximation of temporal video data using linear Bezier fitting. For a given sequence of frames, the proposed method estimates the intensity variations of each pixel in temporal dimension using linear Bezier fitting in Euclidean space. Fitting of each segment ensures upper bound of specified mean squared error. Break and fit criteria is employed to minimize the number of segments required to fit the data. The proposed method is well suitable for lossy compression of temporal video data and automates the fitting process of each pixel. Experimental results show that the proposed method yields good results both in terms of objective and subjective quality measurement parameters without causing any blocking artifacts.Comment: 14 Pages, IJMA 201

Equal Sum Sequences and Imbalance Sets of Tournaments

Reid conjectured that any finite set of non-negative integers is the score set of some tournament and Yao gave a non-constructive proof of Reid's conjecture using arithmetic arguments. No constructive proof has been found since. In this paper, we investigate a related problem, namely, which sets of integers are imbalance sets of tournaments. We completely solve the tournament imbalance set problem (TIS) and also estimate the minimal order of a tournament realizing an imbalance set. Our proofs are constructive and provide a pseudo-polynomial time algorithm to realize any imbalance set. Along the way, we generalize the well-known equal sum subsets problem (ESS) to define the equal sum sequences problem (ESSeq) and show it to be NP-complete. We then prove that ESSeq reduces to TIS and so, due to the pseudo-polynomial time complexity, TIS is weakly NP-complete.Comment: Presented at the Retrospective Workshop on Discrete Geometry, Optimization and Symmetry, 25-29 Nov 2013, The Fields Institute, Toronto, Canad

Perturbative Matching of Heavy-Light Currents with NRQCD Heavy Quarks

We present further results for one-loop matching of heavy-light axial and vector currents between continuum QCD and a lattice theory with NRQCD heavy quarks and massless clover quarks.Comment: LATTICE98(heavyqk

S-wave charmed mesons in lattice NRQCD

Heavy-light mesons can be studied using the 1/M expansion of NRQCD, provided the heavy quark mass is sufficiently large. Calculations of the S-wave charmed meson masses from a classically and tadpole-improved action are presented. A comparison of O(1/M), O(1/M^2) and O(1/M^3) results allows convergence of the expansion to be discussed. It is shown that the form of discretized heavy quark propagation must be chosen carefully.Comment: LATTICE98(heavyqk), 3 pages including 3 figure