Investigating economic synergy in the spatial structure of Tehran metropolitan region

Economic synergy is essential in functional polycentric metropolitan regions due to their high collaborative potential between area centers and subcenters, which results in greater competition. Our results indicate that, based on the theory of economic geography, economic activities in metropolitan regions tend to be concentrated and agglomerated initially due to economies of scale, before intentionally decentralizing due to diseconomies of scale arising from agglomeration. The spatial structure of metropolitan regions also tends to be morphologically polycentric, although there is evidence for a tendency toward functional polycentricity as well. Tehran metropolitan region has attracted industrial workshops over time due to the economies of scale and agglomeration economies, which in turn have increased functional centralization and spatial concentration in the region. Yet in recent decades, after the implementation of spatial policies of economic synergy, both the rate of specialization and diversification in the region's production structure have gradually increased; this can be considered a result of spatial policies of economic synergy. The example of Tehran's illustrates how policing strategies can promote a region's transition from monocentric to functional polycentric, enhancing the economic role of medium‐sized cities, creating specialized centers and clustered enterprises, and supporting network interaction between urban centers.