Source: wikibot/subgame-perfect-equilibrium
= Subgame perfect equilibrium
{wiki=Subgame_perfect_equilibrium}
Subgame Perfect Equilibrium (SPE) is a refinement of Nash Equilibrium used in game theory, specifically in the context of extensive-form games, which can be represented by a tree-like structure. In an SPE, the strategy profile is not only a Nash Equilibrium in the game as a whole but also remains a Nash Equilibrium in every subgame of that game.