No matter what reason you want to know, it is difficult for someone to give you a very comprehensive and detailed discussion.

I mainly answer from one side.

========================================================================

The most direct application of economic theory in comprehensively deepening reform is the famous conclusion of the Third Plenary Session of the 18th CPC Central Committee:

"Economic restructuring is the focus of comprehensively deepening reform. The core issue is to correctly handle the relationship between the government and the market, so that the market can play a decisive role in resource allocation and better play the role of the government. "

According to the general equilibrium theory of western economics, the equilibrium price of commodities in a perfectly competitive economy has reached the Pareto optimal state of production and exchange. Only in a competitive market economy can economic resources be optimally allocated and economic efficiency be maximized. Any unnecessary and inappropriate intervention in the market mechanism can only hinder the optimal allocation of resources and reduce economic efficiency.

Looking back at the history of China's market economic system reform, we can find that since the 14th National Congress of the Communist Party of China made it clear that the socialist market economic system is the goal of economic system reform, we have successfully realized the great historical transformation from a highly centralized planned economic system to a dynamic socialist market economic system through all-round reform with economic system reform as the core. China has gradually formed an all-directional, wide-ranging and multi-level opening-up pattern. Over the past 30 years of reform and opening up, China's GDP has grown at an average annual rate of nearly 10%, and people's living standards have steadily improved. All these achievements in economic construction show that the goal of socialist market economic system reform is correct, and giving full play to the role of the market in resource allocation will really help to further liberate and develop productive forces and ensure the sustained and healthy development of the national economy.

"Making the market play a decisive role in resource allocation" shows that the relationship between the government and the market is more clear. Emphasizing the decisive role of market economy in the allocation of resources actually affirms that market economy will rationally allocate resources in a time process. Because, with the help of market prices, we should solve the major problems of what to produce, how to produce it and for whom. Behind the seemingly chaotic surface of market economy, there are economic laws at work. Of course, the market will also fail, and production and redistribution especially need government policies and regulation.

To establish a socialist market economic system, the core issue is to correctly handle the relationship between the government and the market, and its essential feature is the organic combination of the basic socialist system and the market economy. After years of hard work, the conditions for decisive market adjustment have taken shape. For example, in China's total commodity circulation, market regulation has accounted for more than 90%. China's macro-control mode is gradually improving, from relying on a single administrative means to focusing on economic means and combining legal means with administrative means. It is against this background that we are more confident to play a decisive role in the market.

Accordingly, we should follow the general law of market economy that the market determines the allocation of resources, improve the socialist market economic system, and focus on solving the problems of imperfect market system, excessive government intervention and inadequate supervision. Actively and steadily push forward the market-oriented reform in breadth and depth, greatly reduce the direct allocation of resources by the government, and promote the allocation of resources to maximize benefits and optimize efficiency in accordance with market rules, market prices and market competition.

========================================================================

In addition, we can also discuss the application of economic theory from the details of other comprehensive deepening reforms.

For example:

The application of macroeconomic theory in "how to give full play to the role of government";

The application of externalities, public goods and property rights economics theory in the construction of ecological civilization;

Wait a minute.

Above.