A decisive strategic advantage is a position of strategic superiority sufficient to allow an agent to achieve complete world domination.
Note that this notion is relative to the agent's situation: a technology that would allow one to dominate the world in year 1000 might no longer be sufficient today.
Bostrom, Nick (2014) Superintelligence: Paths, Dangers, Strategies, Oxford: Oxford University Press, ch. 5
Christiano, Paul (2019) What failure looks like, LessWrong, March 17.
Kokotajlo, Daniel (2019) Soft takeoff can still lead to decisive strategic advantage, LessWrong, August 23.
Tegmark, Max (2017) Life 3.0: Being Human in the Age of Artificial Intelligence, New York: Knopf.
Note that this notion is relative to the agent's situation: for example, a technology that would allow one to dominate the world in year 1000 might no longer be sufficient today.