早在1817年,经济学家李嘉图就已经在其代表作《政治经济学及赋税原理》中指出,一个地区只要集中生产其具有比较优势的产品,买入其他地方生产具有比较优势的产品,它就能从贸易中获益。但是,时至今天,国家之间还有不少贸易壁垒。放眼国内,虽然地方之间的商品和要素流动没有面临关税,但国内经济学家发现地方保护严重~(〔1〕),导致一定程度的市场分割~(〔2〕)。这影 As early as 1817, Ricardo, an economist, had already pointed out in his masterpiece “Political Economy and Principles of Taxation” that in a region, as long as it concentrates on producing products with comparative advantages and buying elsewhere to produce products with comparative advantages, Can benefit from trade. However, to this day, there are still many trade barriers between countries. Looking at China, although there is no tariff on the flow of goods and elements between regions, domestic economists find that local protection is serious and lead to a certain degree of market segmentation (2). This shadow