In the approximate factor model of asset returns developed by Chamberlain and Rothschild (1983), the random return on each of n assets is a linear combination of k common factors plus an asset specific random return, where n is large and k is small. The asset-specific returns are only weakly correlated, in the sense that the largest eigenvalue of the covariance matrix of asset-specific returns is bounded above for all n. This implies that the risk in portfolios with holdings spread thinly over many assets comes only from the common factor returns, not from the asset-specific returns. The factor returns capture nondiversifiable risks, which arise from economy-wide shocks, whereas the asset-specific returns capture diversifiable risks, which arise from the idiosyncratic movements of individual security prices.
APC’s Universal Notebook Battery is a slim and lightweight external battery pack which provides up to 8-hours of continuous runtime (actual runtimes may vary by notebook model and power setting).
Features:
• Ultra-lightweight construction reduces bulk and weight in notebook carry-on luggage.
• Wide range of selectable output voltages power most notebook computers.
• Four charge/discharge level indicators.
• Letter-coded power tips provided compatibility with most notebook computers (see Compatibility Guide).
• Compatible with APC’s TravelPower Adapter and Universal Power Adapter models.
• 80 Watts of continuous power, up to 100 Watts peak power output.
• Up to 8 hours of continuous runtime for your notebook.
Business cycle theory concerns the description and explanation of the observed ups and downs of main macroeconomic variables. After the early attempts to provide informal and non mathematical explanations, based on verbal arguments and empirical observations, the business cycle theory has been mainly considered a problem of mathematical economics after the works by Samuelson [28] and Hicks [16]. So, a business cycle model is now considered a dynamic model, usually formulated in the framework of the theory of dynamical systems, whose mathematical structure allows for fluctuations in major macroeconomic variables. A broad, and purely formal, classification of business cycle models distinguishes between linear and nonlinear, continuous and discrete time models.
