xBookUtils.terms['fn_2_501'] = "Throughout this book, we often use the word “good” to mean both tangible goods, like trucks, computers, jewelry, and so on; and services, like haircuts, dog walking, financial planning, and so on. In this usage, anything a consumer values—tangible or not, concrete or abstract—is a good.";
xBookUtils.terms['fn_2_502'] = "Economists often draw demand curves as straight lines, and we do so as well throughout much of this book. This is really just for convenience. As their name suggests, demand curves in reality are normally curved.";
xBookUtils.terms['fn_2_503'] = "An interesting but unusual exception to this is a Giffen good, which has an upward-sloping demand curve. We will discuss such goods in Chapter 5. Demand curves for regular (non-Giffen) goods can also sometimes be flat, as we discuss in the next section. We explore the deeper reasoning behind why demand curves usually slope down in Chapters 4 and 5.";
xBookUtils.terms['fn_2_504'] = "When we use the word “shift,” this includes not only parallel shifts of the demand curve, as shown in Figure 2.2, but also rotations (which change the steepness or slope of a demand curve). Later we discuss what economic forces affect the slopes of demand curves.";
xBookUtils.terms['fn_2_505'] = "We typically expect that supply curves slope upward, although in some cases (especially in the long run), they may be horizontal, and in others they might be perfectly vertical. We will discuss these special cases later.";
xBookUtils.terms['fn_2_506'] = "Note that, just like demand curves, there’s no requirement that supply curves be linear. We just draw them as such for simplicity.";
xBookUtils.terms['fn_2_507'] = "Prices can sometimes remain at levels other than their equilibrium value for extended periods of time, especially if there are policy-based interventions in the market, such as price ceilings (maximum prices allowed by law) or price floors (minimum prices prescribed by law). We discuss these sorts of situations in Chapter 3.";
xBookUtils.terms['fn_2_508'] = "Glenn Ellison and Sara Ellison, “Search, Obfuscation, and Price Elasticities on the Internet,” Econometrica 77, no. 2 (2009): 427–452.";
xBookUtils.terms['fn_2_509'] = "For a linear demand curve that intersects both the price and quantity axes, the point where the demand curve is unit elastic is always the midpoint. The curve’s slope equals the price where it crosses the vertical axis (call this PY) divided by the quantity where it crosses the horizontal axis (call this QX), so 1 over the slope equals –QX/PY. The price-to-quantity ratio at the midpoint equals (PY/2)/(QX/2), or simply PY/QX. The elasticity, which is the product of these two ratios, must therefore equal –1.";
xBookUtils.terms['fn_2_510'] = "Aviv Nevo, “Measuring Market Power in the Ready-to-Eat Cereal Industry,” Econometrica 69, no. 2 (2001): 307–342.";