Table 2.

Judgment of coupling degree, coupling coordination degree and classification of discrimination relation.

Coupling degree judgment	Coupling phase	Coupling coordination degree judgment	Coupling coordination level	System index comparison	Relational discrimination feature
C = 0	Coupled independence	0 ≤ D < 0.2	Severe dysregulation	0 < $S_1^{\prime }/{\text{S}}_2^{\prime }$ ≤ 0.3	Green technology innovation lags behind
0 < C < 0.1	Coupling start	0.2 ≤ D < 0.3	Moderate dysregulation	0.3 < $S_1^{\prime }/{\text{S}}_2^{\prime }$≤ 0.5	Green technology innovation generally lags behind
0.1 ≤ C < 0.3	Coupling antagonism	0.3 ≤ D < 0.4	Mild disorder	0.5 < $S_1^{\prime }/{\text{S}}_2^{\prime }$ ≤ 0.8	Green technology innovation lags slightly
0.3 ≤ C < 0.5	Coupling running-in	0.4 ≤ D < 0.5	Borderline disorder	0.8 < $S_1^{\prime }/{\text{S}}_2^{\prime }$  ≤ 1.2	Basic synchronization
0.5 ≤ C < 0.8	Coupling growth	0.5 ≤ D < 0.6	Primary coordination	1.2<$S_1^{\prime }/{\text{S}}_2^{\prime }$  ≤ 2.0	The digital economy is lagging slightly
0.8 ≤ C < 1.0	Coupling maturation	0.6 ≤ D < 0.7	Intermediate coordination	2.0 < $S_1^{\prime }/{\text{S}}_2^{\prime }$  ≤ 3.0	The digital economy generally lags
C = 1.0	symbiosis	0.7 ≤ D ≤ 1.0	Advanced coordination	$S_1^{\prime }/{\text{S}}_2^{\prime }$ > 3.0	The digital economy is lagging badly