A general theory of innovation and progress in human society is outlined, based on the combat between two opposite forces (conservatism/inertia and speculative herding “bubble” behavior). We contend that human affairs are characterized by ubiquitous “bubbles”, which involve huge risks which would not otherwise be taken using standard cost/benefit analysis. Bubbles result from self-reinforcing p...

This article shows that portfolio constraints can give rise to rational asset pricing bubbles in equilibrium even if there are unconstrained agents in the economy who can benefit from the induced limited arbitrage opportunities. Furthermore, it is shown that bubbles can lead to both multiplicity and real indeterminacy of equilibria. The general results are illustrated by two explicitly solved e...

Recent studies show that individual investors tend to speculate on stock markets and hold shares with a lottery-like return. For this speculation of people have a significant impact on stock returns, individual investors must trade the same shares with the same time. The purpose of this study was to investigate the effect of the speculative bubble on the stock returns of companies in Iran. Foll...

Statistical analysis of financial data most focused on testing the validity of Brownian motion (Bm). Analysis performed on several time series have shown deviation from the Bm hypothesis, that is at the base of the evaluation of many financial derivatives. We inquiry in the behavior of measures of performance based on maximum drawdown movements (MDD), testing their stability when the underlying...

We develop a model in which boundedly rational agents apply technical and fundamental analysis to identify trading signals in two different speculative markets. Whether an agent trades and, if so, in which market with which strategy depends on profit considerations. As it turns out, an ongoing evolutionary competition between the trading strategies causes complex price dynamics which closely re...

We study the existence of equilibrium and rational bubbles in a Ramsey model with heterogeneous agents, borrowing constraints and endoge-

ijtihad, jurisprudence in religion and imitation that is fojiowing a just religious leader in divine commandments, are fundamental issues in islamic society and are necessary for continuation of divine religion. this article turns to understanding the conception, necessity, beginning and evolution of ijtihad and imitation (taqlid), if s rational and traditional reasons using quran, and also ref...