Growth mechanism of the digital economy network in urban agglomerations of the Yangtze River Economic Belt

This paper examines 60 cities in China’s Yangtze River Economic Belt. Using the panel entropy method to measure the level of digital economic development, employing a modified gravity model and social network analysis to reveal how network structural characteristics evolve dynamically, and how roles and functions transform among different regions, as the spatial interconnection network of the digital economy grows in the Yangtze River Economic Belt and its three major urban agglomerations. The temporal exponential random graph model is used to analyze the factors that influence network growth mechanisms and their heterogeneity. The research findings indicate that: (1) The spatial interconnection network of the digital economy in the Yangtze River Economic Belt exhibited a hub-and-spoke ‘core–semi–periphery–periphery’ structure. Giving rise to two representative development models and four major communities characterized by ‘high cohesion and low coupling’. (2) The digital economy network along the Yangtze River Economic Belt exhibits temporal restructuring of role functions, intensified cross-regional spillover effects, the dynamic migration of structural hole nodes, and the succession of core cities. Network complexity and intermediary effects have significantly increased. (3) Endogenous structures, such as mutual connections, contribute to network growth, while the attributes of external nodes, such as openness, need to be promoted through mechanisms, including market regulation, to facilitate this growth. The growth path of this network exhibits characteristics of both path dependence and path creation. (4) The growth mechanisms of spatial networks for the digital economy within the three major urban agglomerations exhibit heterogeneity. In terms of internal structure, the Yangtze River Delta forms an open triad, while the Yangtze River Middle Reach and Chengyu urban agglomeration form closed triads. The effects of geographical distance exhibit significant differentiation, with networks of nearby cities in the Yangtze River Delta and Yangtze River Middle Reach being more likely to grow, while networks of distant cities in the Chengyu urban agglomeration are more prone to growth.