public goodpubic good.docVIP

Public good In economics, a public good is a good that is both non-excludable(非排他性） and non-rivalrous（非竞争性） in that individuals cannot be effectively excluded from use and where use by one individual does not reduce availability to others.[2] 在经济学中，公共非排他性和非竞争性，使用和在哪里使用A fireworks display is a public good because it is non-excludable (impossible to prevent people from using it) and non-rivalrous (one individuals use does not reduce availability to others). 烟火表演是公共物品以为具有非排他性和非竞争性。 非排他性指的是某人在消费一种公共物品时,不能排除其他人消费这一物品 ，是指当一个人消费该物品时并不会减少其他人对这种物品的消 Gravelle and Rees: The defining characteristic of a public good is that consumption of it by one individual does not actually or potentially reduce the amount available to be consumed by another individual. Public goods include fresh air, knowledge, lighthouses, national security, flood control systems and street lighting. Public goods that are available everywhere are sometimes referred to as global public goods.[1] There is an important conceptual difference between the sense of a public good, or public goods in economics, and the more generalized idea of the public good (or common good, or public interest),[3][4]‘the’ public good is a shorthand signal for shared benefit at a societal level [this] (philosophical/political) sense should not be reduced to the established specific (economic) sense of ‘a’ public good.[5] Many public goods may at times be subject to excessive use resulting in negative externalities affecting all users; for example air pollution and traffic congestion. Public goods problems are often closely related to the free-rider problem, in which people not paying for the good may continue to access it. Thus, the good may be under-produced, overused or degraded.[6] Public goods may also become subject to restrictions on access and may then be considered to be club goods or private goods; exclusion mechanisms include copyright, patents, congestion pricing, and pay television. There is a good deal of debate