A Stackelberg leader will necessarily make at least as much profit as he would if he acted as a Cournot oligopolist.

Stackelberg Leader

A firm in a duopoly that moves first to set its output level, thereby determining the market's price and influencing the subsequent behavior of a follower firm.

Cournot Oligopolist

A firm competing in a market where a few firms control the majority of the market share and where each firm takes into account its rivals' production quantities when determining its own quantity.