$c$

Manufacturer’s unit cost of production

$w$

Wholesale price

$p$

Sales price

$a$

Potential market size

$\theta$

Product greenness

$\rho$

Consumer preferences for offline retail channels

$b$

Cross-price elasticity of demand

${\beta }_r$

Demand sensitivity to product greenness in offline channels

${\beta }_m$

Demand sensitivity to product greenness in online channels

$\eta$

Sensitivity of green research and development costs to product greenness

$d_r,d_m$

The demand for offline retail channels, online direct sales channel demand

${\pi }_m,{\pi }_r,\pi$

Respectively, the profits of manufacturers, retailers, supply chain