A small number of sellers in a market makes rigorous competition:

Question

Quizplus · Accepted Answer

If there are only a small number of sellers in a market, it is more likely that there will be less competition and strategic interactions among them will be vitally important. This is because with fewer competitors, each seller has a greater share of the market and therefore more power to affect prices and market outcomes. This makes strategic interactions, such as collusion or price-fixing, more attractive and necessary for these sellers to maintain their power and profits.

A Small Number of Sellers in a Market Makes Rigorous