Urban agglomerations like the Guangdong-Hong Kong-Macau Greater Bay Area are important for economic development. Cities within these areas need to work together to attract resources and investments. However, sometimes cities compete instead of cooperating, leading to problems like industry duplication and uneven development. In this study, researchers looked at 11 cities in the Greater Bay Area to see how they interact economically. They found that these cities have different strengths and weaknesses, and they often compete or complement each other. The researchers identified three types of relationships between cities: competition, complementarity, and non-relation. By understanding these relationships, cities can better develop their economies by working together effectively.