Comparative statics and duality theory

2021 ◽  
pp. 173-208
Author(s):  
Harald Wiese
Author(s):  
Jamal Othman ◽  
Yaghoob Jafari

Malaysia is contemplating removal of most of her subsidy support measures including subsidies on cooking oil which is largely palm oil based. This paper aims to examine the effects of cooking oil subsidy removals on the competitiveness of the oil palm subsector and related markets. This is done by developing and applying a comparative static, multi-commodity, partial equilibrium model with multi-stages of production function for the Malaysian perennial crops subsector which explicitly links different stages of production, primary and intermediate input markets, trade, and policy linkages. Results partly suggest that export of cooking oil will increase by 0.2 per cent due to a 10 per cent cooking oil subsidy reduction, while domestic output of cooking oil may eventually see a net decline of 1.97 per cent. The results clearly point out that the effect of reducing cooking oil subsidies is relatively small at the upstream levels and therefore it only induces minute effects on factor markets. Consequently, the market for other agricultural crops is projected to change very marginally.   Keywords: Multicomodity, comparative statics, partial equilibrium model, output supply-factor markets linkages, effects of cooking oil subsidy removals.


1991 ◽  
Vol 8 (1) ◽  
pp. 109-127
Author(s):  
Zaidi Sattar

The present paper is a contribution to the building blocks of an investmentmodel within the framework of an integrated macroeconomic model of anIslamic economy. Investment behavior in the model is guided by an Islamicethicalvalue system and profit-sharing financial contracts. The typical firm’sinvestment decision is believed to emerge from a dynamic inter-temporalmaximization exercise within an infinite time horizon. The method of Calculusof Variations is applied to arrive at the optimal investment and employmentcriteria for the firm. The result is then incorporated into a macroeconomicmodel to study the behavior of key endogenous variables like national incomeand the rate of profit-share. Comparative statics exercised within a generalequilibrium framework reveal the potency of monetary policy but the neutralityof fiscal policy with respect to output and employment.IntroductionThe past decade has witnessed a tremendous outpouring of interest aswell as effort in the formalization of economic models based on profit-sharingfinancial arrangements as an Islamic alternative to the conventional interestbasedeconomic system. Several macroeconomic models for interest-freeeconomies have been proposed (Anwar 1987; Habibi 1987; Metwally 1981& 1983). The rigor of an integrated approach to such macroeconomic modelhgdepends on the rigor of the component models, namely, the consumption,investment, monetary, and fiscal relationships. Economists have writtenextensively on different aspects of consumer behavior in Islamic societies.Kahf (1978) and Khan (1984), among others, have contributed to the conceptualand analytical formulation of the consumption function under ...


Author(s):  
David A. Malueg ◽  
Andrew James Yates
Keyword(s):  

2021 ◽  
Vol 36 ◽  
Author(s):  
Sergio Valcarcel Macua ◽  
Ian Davies ◽  
Aleksi Tukiainen ◽  
Enrique Munoz de Cote

Abstract We propose a fully distributed actor-critic architecture, named diffusion-distributed-actor-critic Diff-DAC, with application to multitask reinforcement learning (MRL). During the learning process, agents communicate their value and policy parameters to their neighbours, diffusing the information across a network of agents with no need for a central station. Each agent can only access data from its local task, but aims to learn a common policy that performs well for the whole set of tasks. The architecture is scalable, since the computational and communication cost per agent depends on the number of neighbours rather than the overall number of agents. We derive Diff-DAC from duality theory and provide novel insights into the actor-critic framework, showing that it is actually an instance of the dual-ascent method. We prove almost sure convergence of Diff-DAC to a common policy under general assumptions that hold even for deep neural network approximations. For more restrictive assumptions, we also prove that this common policy is a stationary point of an approximation of the original problem. Numerical results on multitask extensions of common continuous control benchmarks demonstrate that Diff-DAC stabilises learning and has a regularising effect that induces higher performance and better generalisation properties than previous architectures.


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