what is the difference between subgame perfect equilibrium and nash equilibrium
Subgame perfect equilibrium In game theory, a subgame perfect equilibrium (or subgame perfect Nash equilibrium) is a refinement of a Nash equilibrium used in dynamic games. A strategy profile is a subgame perfect equilibrium if it represents a Nash equilibrium of every subgame of the original game. Informally, this means that if the players played any smaller game that consisted of only one part of the larger game, their behavior would represent a Nash equilibrium of that smaller game. Every finite extensive game has a subgame perfect equilibrium.[1]
Inferior good In economics, an inferior good is a good whose demand decreases when consumer income rises (or demand rises when consumer income decreases),[1] unlike normal goods, for which the opposite is observed.[2] Normal goods are those for which demand rises as consumer income rises. [3] This would be the opposite of a superior good, one that is often associated with wealth and the wealthy, whereas an inferior good is associated with lower socio-economic groups.