game theory
A mathematical framework for analyzing strategic interactions. Often used in economics, political science, and biology. The term ゲーム理論 (without の) is more common in modern usage.
See also: ゲーム理論
Game theory is often used in economics.
He is researching game theory.
From English 'game theory', calqued as ゲーム (game) + の (possessive particle) + 理論 (theory).