To complete the stylish extension, a number of the property’s existing hardwood windows have also been sympathetically replaced. Tasked with identifying a system that could match the visual appeal of the original wooden frames whilst offering improved quality, usability and security, the Dortech team took the innovative step of suggesting a change to aluminium. After reviewing alternative products on the market, Senior’s high quality PURe® aluminium windows were found to significantly outperform cheaper aluminium systems and offer the perfect solution in terms of both performance and aesthetics. Widely respected for its expertise in high-end aluminium glazing products, Fenster was approached by programme-makers and asked to supply a premium-quality sliding door. In the face of market failure, coase has given the opposite answer: external-utility problems can be solved by explicitly using the market, without government intervention. And zhang wuchang is more absolute, he said that there is no so-called external utility, there is only unclear property rights. Anyway, coase brought revolutionary innovation to market concepts. He made it clear that the key to the market was not the "price mechanism" of impersonal machinery, but the power of participants in economic activity. Central bankers' tasks are limited to keeping inflation stable and independence easier to maintain. Given this narrow mandate, the allocation of central bank decisions is limited. Moreover, it is easier to explain how the central bank's policy tools are linked to its political mandate.