Pronunciation: [sˈʌbɡe͡ɪm] (IPA) 
Subgame is a word in game theory that refers to a smaller game that arises within a larger game. The spelling of subgame follows the English spelling rules, where the initial sound of the word is /s/ followed by the short vowel /ʌ/ and then the voiced stop /b/. The final sound is /geɪm/, pronounced as /g/ followed by the long vowel /eɪ/ and then the voiced stop /m/. Therefore, the IPA phonetic transcription for subgame is /ˈsʌbgem/.
A subgame refers to a specific phase or portion of a larger game or decision-making situation. It denotes a self-contained set of moves and decisions that occur within the overall game or scenario. It can also be defined as a smaller, independent game within a larger game that arises from a particular point, decision, or set of actions taken by the players involved.
The concept of subgames is commonly used in game theory, particularly in the study of extensive-form games, which include sequential or dynamic decision-making situations. In these games, each player takes turns making decisions or moves based on the outcomes and actions of previous players. Subgames typically arise when players reach a decision node, and depending on the choices made at that node, a new, smaller game with its own set of possible outcomes and actions may emerge.
The analysis of subgames focuses on the specific strategies, payoffs, and outcomes within that isolated game. It may involve examining the best choices for the players, identifying dominant strategies, or determining the equilibria in that particular subgame. Understanding the dynamics of subgames can provide valuable insights into the overall game, as the strategies employed in one subgame may affect the strategies and outcomes in subsequent subgames or in the complete game.
Overall, a subgame represents a distinct and self-contained game or decision-making scenario within a larger game, allowing for a more focused analysis of specific strategies and outcomes that influence the overall game's progress and outcome.
The word "subgame" derives from the combination of two terms: "sub-" and "game".
The prefix "sub-" comes from the Latin prefix "sub-", meaning under, below, or beneath. It often indicates something less than or subordinate to the root word. In this case, "sub-" implies that a subgame is a smaller or lesser part of a larger game.
The term "game" originated from the Old English word "gamen", which referred to "fun, joy, amusement, or entertainment". Over time, it evolved to encompass activities involving competition, rules, and outcomes. In the context of subgame theory, a subgame is a game within a larger game that emerges due to specific conditions or decision points.
Therefore, combining the prefix "sub-" with "game" creates the term "subgame" to indicate a smaller game or a game within a game.
