Decision theory vs. Game theory? Game theory is defined (here) as follows:


  "Game theory, branch of applied mathematics that provides tools for
  analyzing situations in which parties, called players, make decisions
  that are interdependent. "


And Decision theory is defined (here) as follows:


  "Decision theory is concerned with the reasoning underlying an agent’s
  choices."


Regarding to above definitions, can we say that Decision theory is a subset of Game theory? Or they are completely two different concepts? And in general, what are their common points?
Game theory has people as players, decision theory has probability distributions of decision networks. Game theory is concerned with what the probability and utility need to be to model an observed outcome. The probabilities and utilities are sometimes modelled as piecewise functions. Decision theory uses a prior probability to predict potential outcomes. Such potential outcomes might be a Markov chain. Game Theory is mathematical, decision theory is statistical, if the distinction makes sense. There are overlaps, but that is true with everything. I do not believe that decision theory is a subset of game theory.
Game theory has people as players, decision theory has probability distributions of decision networks. Game theory is concerned with what the probability and utility need to be to model an observed outcome. The probabilities and utilities are sometimes modelled as piecewise functions. Decision theory uses a prior probability to predict potential outcomes. Such potential outcomes might be a Markov chain. Game Theory is mathematical, decision theory is statistical, if the distinction makes sense. There are overlaps, but that is true with everything. I do not believe that decision theory is a subset of game theory.