## 4 Results
### Results of Spatiotemporal Evolution Analysis
#### 4.4.2 Spatial Variation Results  
Table 3 and Figure 6 present the results based on the decomposition of the Dagum Gini coefficient. This study provides an in-depth analysis of the spatial differences in the coordinated development of regional green technology innovation and carbon reduction in the construction industry from 2013 to 2021. According to Table 3, the overall Gini coefficient (G) for the 30 provinces and municipalities in the country shows a continuous downward trend, decreasing from a maximum of 0.127 in 2013 to 0.091 in 2019, before slightly rebounding to 0.094 in 2021. This indicates that the coordinated development of RGTI, NQP, and CRCI generally exhibits a convergent characteristic. Specifically, although the inter-regional disparity component decreased from 0.078 in 2013 to 0.068 in 2021, the inter-regional disparity remains a major characteristic causing significant regional differences among the four major regions. This is also validated in Figure 6, which shows through the difference decomposition results for the four major regions that inter-regional disparity has always been the dominant factor of inequality, with its contribution rate rising significantly from 62% in 2013 to 72% in 2021. This indicates that although the gap between developed and underdeveloped regions in terms of green technology application and carbon reduction has narrowed, structural differences remain significant. The coastal eastern region, benefiting from the advantages gained since the reform and opening up, has significant advantages in the allocation of innovative resources, technological investment, and industrial structure transformation, not only consolidating higher education institutions and research agencies but also possessing more complete innovation conditions and capital markets [50]. In contrast, the central and western regions have long faced structural challenges, including a shortage of innovative elements, lower industrial levels, and limited financial support. Meanwhile, the intra-regional disparity component exhibits a continuous decline trend from 0.029 to 0.019, accounting for 20-23% of the total disparity, reflecting a continual strengthening of consistency within each region. Moreover, the hyper-variance density decreased from a maximum of 0.019 to 0.008, indicating that the extreme degree of differentiation in regional development has significantly weakened. These empirical findings highlight critical characteristics of China's regional green development. Although overall spatial disparities are converging, the relative importance of inter-regional differences continues to increase, underscoring persistent structural challenges in achieving regional coordination. In particular, the sustained rise in the share of  
\begin{table}
\begin{tabular}{c c c c c} \hline
**Year** & **Overall Variance G** & **Intra-Regional Variance** & **Inter-Regional Variance** & **Hypervariance Density** \\ \hline
2013 & 0.127 & 0.029 & 0.078 & 0.019 \\
2014 & 0.113 & 0.026 & 0.071 & 0.016 \\
2015 & 0.108 & 0.024 & 0.068 & 0.016 \\
2016 & 0.105 & 0.023 & 0.06  
inter-regional differences emphasizes the necessity of in-depth examination of regional heterogeneity. Therefore, future research should focus on the specific characteristics and interaction mechanisms of the eastern, central, western, and northeastern regions. Table 4 presents the differential characteristics of coordinated development within the four major regions of China from 2013 to 2021. A systematic analysis of the Gini coefficients (G values) within subgroups of each region reveals significant intra-regional disparity characteristics and their evolutionary trends. The results indicate that the internal differences in the eastern region are the most pronounced, with an average G value of 0.104, which, although decreasing gradually from 0.118 in 2013 to 0.093 in 2021, remains significantly higher than in other regions.