Unifying static and dynamic perspectives to assess spatial mismatch in polycentricity: Evidence from Beijing, China

Polycentric development is widely recognized as an ideal spatial model for megacities, yet its implementation often falls short in the contexts of rapid expansion and suburbanization. Addressing this discrepancy demands a critical examination of urban form and inter-centre relationships. By leveraging large-scale mobile phone data, this study integrates static density distributions with dynamic mobility patterns to establish a conceptual framework for examining the internal structure and functional interdependencies within both cores and peripheries. We propose a novel methodology that combines spatial autocorrelation and the Leiden algorithm to identify Urban Employment Centres (UECs) across weekdays and weekends. The findings reveal a dual reconfiguration of the urban system: (1) the fragmentation of a historically contiguous core into large, distinct UECs, and (2) the integration of dispersed suburban settlements into small, individual UECs. While rank-size distributions indicate balanced employment and flow densities, network analysis reveals a pronounced capability hierarchy: a minority of UECs control resource agglomeration and diffusion, confining others to peripheral roles. This indicates that the nominal polycentric strategy has not developed as anticipated, but instead perpetuates monocentric path dependence. Moreover, geographical constraints and core-city dominance continue to impede cooperative networks between centres, thereby exacerbating core-periphery disparities in evolving megacities. This study advances a scalable diagnostic framework, enabling consistent assessment of polycentricity across institutional, cultural, and developmental contexts. Its findings provide policymakers with actionable strategies to reconcile polycentric goals with compact development, fostering equitable and sustainable transitions in megacities.