We analyse how market competition in a vertically differentiated polluting industry is affected by product variants that comply at different levels with "green" social norms. A green consumption behaviour is considered as a byword of good citizenship. Consumer preferences depend on a combination...

We prove that a sufficient condition for the core existence in a n-firm vertically differentiated market is that the qualities of firms' products are equally-spaced along the quality spectrum. This result contributes to see that a fully collusive agreement among firms in such markets is more...