“3060碳达峰碳中和”双碳目标作为一个国家战略部署，有许多理论和实践问题急需解决，其中企业的低碳生产策略选择以及企业和政府之间的相互作用是我们关注的重点。企业的低碳生产策略选择问题是指如何使不同市场竞争程度行业内的企业选择低排放、低污染的生产模式的问题。从理论角度看，已有从完全垄断、双寡竞争、完全竞争等单一市场结构的角度来研究企业的低碳生产策略选择问题，虽然取得了大量的有政策管理意义的研究成果，但迄今并未形成较为统一的理论分析框架；而从实践角度上看，实现双碳目标涉及政府、企业等多个主体，而企业的生产策略选择既受到政府低碳政策引导的影响，又受到产品市场容量、产品之间的替代性、竞争企业的数量也就是市场竞争程度等多个因素的影响，具有复杂系统的典型特征。以系统科学视角出发关注不同行业的市场竞争程度，旨在政府的差异化碳税、统一碳税、碳排放总量约束和碳排放权交易政策背景下，从单一低碳政策、联合低碳政策、短期静态最优、长期动态最优等多个角度建立政府与不同市场竞争程度行业中领头企业相互作用下的博弈模型，进而探究不同市场竞争程度对行业内企业低碳生产策略选择以及对政府低碳政策制定的影响，以期通过对政府低碳政策机制的设计，激励不同行业的企业选择低碳生产策略，实现整个社会的绿色低碳转型。论文主要研究工作及研究发现如下：

首先，不同于以往基于企业单一市场竞争程度的研究，我们建立了政府与不同市场竞争程度行业Stackelberg博弈的统一模型框架。在政府实施差异化碳税政策情景下，探讨了不同市场竞争程度行业的最优生产决策行为，以及政府对差异化最优碳税税率的制定。进一步探究了在哪种单位低碳产品额外成本的区间以及在哪种市场竞争程度的行业中，能够使政府实施碳税政策、企业选择低碳生产策略。分析得到政府与不同市场竞争程度行业在不同策略组合下相互作用的均衡结果构成的嵌套博弈的纳什均衡，进而得到划分政府和整个生产企业系统状态的单位低碳产品额外成本的临界值和市场竞争程度的临界值。对两个临界值进行分析，发现除了可以通过引进新的企业，提高原有市场的竞争程度，还可以通过增加产品市场容量、提高减排成本系数、降低单位产品生产成本等措施来改变临界点的值，使政府实施碳税政策，整个行业的企业选择低碳生产策略且政府的社会福利高于不实施碳税时的社会福利。数值分析了市场竞争程度等参数对企业最优生产决策、行业内领头企业的利润、市场收入以及社会福利的影响。

其次，在统一市场竞争程度框架的基础上，将行业的发展视为一个动态过程，在考虑行业内有企业进入与退出的前提下，研究了新进企业与不同市场竞争程度原市场之间的博弈。分析了新企业进入原市场的前提条件，得出了单个企业逐个进入市场的最优产量递推公式，以及新企业在原市场分别是混合策略、低碳型、传统型三种情形下进入市场的条件和进入市场后的最优决策行为。针对低碳生产方式不同的成本区间，设计了政府具体的差异化碳税税率，以使原来的传统市场被改造，使新企业能够以低碳生产策略进入市场。现有的研究通常是基于单独离散型市场竞争程度，因此现有研究中的最优碳税税率通常是一个孤立的点而不是一个碳税选择的可行区间，我们的结论中包含了中间不同市场竞争程度的结果，并且是一个连续变化的过程，因此得到的是碳税税率选择的可行区间。

再次，不同于以往将碳排放总量作为外生因素的研究，在统一碳税和碳排放总量约束联合政策下，研究了政府如何给不同市场竞争程度的行业制定最优统一碳税税率、最优碳排放总量约束值，以及不同市场竞争程度行业内领头企业如何决策最优传统产品和最优低碳产品的产量。探究了政府的碳排放总量约束分别对不同行业内企业有效的临界值以及能够使不同市场竞争程度行业选择低碳生产策略的碳税税率和碳排放总量约束值。研究发现：政府实施统一碳税无碳排放总量约束时与有碳排放总量约束条件时，行业内企业的最优产量一致，而两种情形下市场收益的最优值是否一致与碳税税率有关。

最后，从长期动态优化决策的角度建立了Stackelberg微分博弈模型，研究了碳排放权交易市场建立初期政府如何根据不同行业的反馈来制定单位碳排放权交易价格。研究发现可以通过增加低碳技术的减排成本系数、增加同一行业内低碳产品与传统产品之间的替代程度以及调整初始碳排放权配额、碳排放存量减少系数等相关参数，能够使行业内碳排放总量峰值降低，达峰时间缩短。外部减排技术对环境中碳排放存量的减少具有明显作用，因此政府可以给具有减排设备或者研发减排技术的企业一定的财政补贴或者税收优惠，以激励减排企业投入更多的资金到减排技术中，从而减少环境中的碳排放存量。

该研究通过综合运用博弈论、最优化理论以及复杂系统等方法，提供了一个研究不同市场竞争程度行业中领头企业与政府中政策制定者博弈的统一理论框架。该研究的相关结果、相关低碳政策机制设计也为企业管理者、政策制定者、促进不同行业的企业向绿色低碳生产模式转型起到了一定的启示作用。

The dual carbon goals of "3060 carbon peaking and carbon neutrality" as a national strategic deployment, present a number of theoretical and practical problems that need to be resolved, with the enterprise's low-carbon production strategy and the relationship between enterprises and the government receiving the majority of our attention. The low-carbon production strategy choice of enterprises refers to the problem of how to make enterprises in industries with different degrees of market competition choose low-emission and low-pollution production patterns. From the theoretical perspective, the problem of low-carbon production strategy choice of enterprises has been studied from the perspective of single market structures such as complete monopoly, duopoly competition, and perfect competition. Although numerous significant research results with policy management have been achieved, a unified theoretical analysis framework has not been established. From the practical perspective, achieving the dual carbon goals involves multiple agents such as government and enterprises, and the production strategy choice of enterprises is affected by both the governmental low-carbon guidance policy and several factors such as the product’s market capacity, substitutability among products, and the number of competing enterprises, i.e., the degree of market competition, which exhibits the typical traits of a complex system. We concentrate on the degree of market competition in various industries from a systems science perspective and aim to establish game models under the interaction between the government and the leading enterprises in industries with various degrees of market competition in the context of the government's differentiated carbon tax, uniform carbon tax, total carbon emission constraint and carbon emissions trading policies, to investigate the effects of various market competition levels on the decision of low-carbon production strategy choice of enterprises in the industry and on the formulation of government low-carbon policies, from the perspectives of single low-carbon policy, joint low-carbon policies, short-term static optimal and long-term dynamic optimal. This research aims to design a low-carbon policy mechanism to motivate enterprises in different industries to choose a low-carbon production strategy and realize the green and low-carbon transformation of the whole society. The main research work and research findings are as follows:

First, different from previous studies based on firms' single degree of market competition, we establish a unified model framework of the Stackelberg game between the government and industries with different degrees of market competition. Under the scenario of the government implementing a differentiated carbon tax policy, we explore the optimal production decision-making behavior of industries with different degrees of market competition and the government's optimal differentiated carbon tax rates decision. We further investigate which interval of extra cost per unit of low-carbon product and in which degree of market competition in the industry can enable the government to implement carbon tax policy and firms to choose low-carbon production strategy. Through the analysis, we obtain the Nash equilibrium of the nested game, which is composed of the equilibrium results of the interaction between the government and industries with different degrees of market competition under different strategy combinations. In turn, we get the critical values of extra cost per unit of low-carbon product and the degree of market competition that divide the state of the government and the entire production enterprise system. By analyzing the two critical values, we find that in addition to introducing new enterprises and increasing the degree of competition in the original market, the values of the two critical points can be changed by increasing the product’s market capacity, increasing the cost coefficient of emission reduction, and reducing the production cost per unit of product, so that the government implements the carbon tax policy, the enterprises of the whole industry choose the low-carbon production strategy and the social welfare of the government is higher than that of the carbon tax is not implemented. Through numerical simulation, we analyze the effects of parameters such as the degree of market competition on firms' optimal production decisions, profits of the leading firm in the industry, market revenues, and social welfare.

Secondly, based on the unified market competition degree framework, we consider the development of the industry as a dynamic process and study the game between new entrants and the original market with different market competition degrees considering the entry and exit of firms in the industry, analyze the preconditions for new firms to enter the original market, and we derive the recursive formula for the optimal output of individual firms entering the market one by one, as well as the conditions for new firms to enter the market under the three scenarios of the original market being mixed strategy, low-carbon, and traditional, respectively, and the optimal decision behavior after entering the market. Furthermore, we design the government-specific differentiated carbon tax rates for different cost bands of low-carbon production strategy to enable the original traditional market to be transformed so that new firms can enter the market with low-carbon production strategy. Previous studies are usually based on individual discrete market competition degrees, so the optimal carbon tax rate is usually an isolated point rather than a feasible interval for carbon tax choice, whereas our conclusions include the results of different intermediate market competition degrees and are a continuous change process, so we derive a feasible range for carbon tax rate selection.

Thirdly, unlike previous studies that treat total carbon emissions as an exogenous factor, we investigate how the government sets the optimal unified carbon tax rate and the optimal total carbon emission constraint value for industries with different market competition degrees under the joint policies of unified carbon tax and total carbon emission constraint, and how the leading enterprises in industries with different market competition degrees make decisions on the optimal quantity of traditional products and low-carbon products. Then, we explore the critical value of the government's total carbon emissions constraint that is effective for enterprises in different industries, respectively, as well as carbon tax rates and total carbon emission constraint values that enable industries with different degrees of market competition to choose low-carbon production strategies. We find that the optimal output of firms in the industry is consistent when the government implements the unified carbon tax without the total carbon emission constraint and the total carbon emission constraint condition, and whether the optimal value of market returns is consistent in the two scenarios is related to the carbon tax rate.

Finally, we develop a Stackelberg differential game model from the perspective of long-term dynamic optimization decisions to investigate how the government sets the unit carbon emission trading price based on the feedback from different industries at the early stage of the carbon trading market establishment. We find that the peak of total carbon emissions in an industry can be reduced and the peak time can be shortened by increasing the abatement cost coefficient of low-carbon technology, increasing the substitution degree between low-carbon products and traditional products in the same industry, and adjusting the initial carbon emission allowance and carbon emission stock reduction coefficient and other related parameters. External emission reduction technology has a significant effect on the reduction of carbon emission stock in the environment, so the government can provide certain financial subsidies or tax incentives to enterprises with emission reduction equipment or researching and developing emission reduction technology, in order to motivate emission reduction enterprises to invest more funds in emission reduction technology, so as to reduce the carbon emission stock in the environment.

This research provides a unified theoretical framework for studying the game between leading enterprises in industries with different degrees of market competition and governmental policymakers by comprehensively using game theory, optimization theory, and complex systems approaches. The relevant results of this study and the design of relevant low-carbon policy mechanisms also provide insights for enterprise managers, policymakers, and the transition to green and low-carbon production patterns for enterprises in different industries.