Laffer curve costs). Although tax policy is often mentioned in relation to supply-side economics, supply-side economists are concerned with all impediments to the supply of goods and services and not just taxation. In their economics textbook "Principles of Economics" (7th edition), economists Karl E. Case of Wellesley College and Ray Fair of Yale University stated "The Laffer curve shows the relationship between tax rates and tax revenues. Supply-side economists use it to argue that it is possible to generate higher revenues by cutting tax rates, but evidence does not appear to support this. The lower tax rates by the Reagan administration decreased
Ibn Khaldun scholars is increasingly common. Influential British historian and international affairs specialist Arnold J. Toynbee has called Ibn Khaldun's Muqaddimah "the greatest work of its kind." Ernest Gellner, once a professor of philosophy and logic at the London School of Economics, considered Khaldun's definition of government the best in the history of political theory. More moderate views on the scope of Ibn Khaldun's contributions have emerged. Arthur Laffer, for whom the Laffer curve is named, acknowledged that Ibn Khaldun's ideas, as well as others, precede his own work on that curve. A focus on understanding the nuances of Ibn Khaldun's contributions