Agglomeration Externalities, Network Externalities and Urban High-Quality Development: A Case Study of Urban Agglomeration in the Middle Reaches of the Yangtze River

The rapid development of the urban network has led to fact that cities are no longer single individuals, and changed environment. interaction between gradually become an important factor for high-quality (HQD) cities. From perspective externalities, it is great significance explore impact agglomeration externalities on HQD promote sustainable region. Taking in middle reaches Yangtze River as example, this study constructs a theoretical framework empirically influence city. results show integrated from 2011 2020 had high clustering coefficient small average path length with characteristics “small world”. centrality nodes was hierarchical “pyramid” structure. 2020, level (HQDL) steadily improved regional “development gap” narrowed. Wuhan, Changsha, Nanchang were relatively advantageous position agglomeration. Furthermore, there spatial effect spillover Network presented difference different cities, u-shaped nonlinear relationship. could significantly HQD, indirect greater than its direct effect. In addition, factors such government capacity opening outside world also significant