最近看文献的时候，看到一句有关博弈论的话，因为我不懂博弈论，所以想请教大家是什么意思：
I have so far focused on Markov perfect equilibria (MPE). In general, such a focus can be restrictive. In this case, however, it can be proved that subgame perfect equilibria (SPE) coincide with the MPE. This will not be true in the next subsection, so it is useful to briefly discuss why it is the case here.

MPE are a subset of the SPE. Loosely speaking, SPEs that are not Markovian will be supported by some type of “history-dependent punishment strategies.” If there is no room for such history dependence, SPEs will coincide with the MPEs.

这段话出处：Acemoglu, D. (2006), Modeling Inefficient Institutions, forthcoming in R. Blundell, W. Newey and T. Persson (eds.), Advances in Economic Theory and Econometrics: Proceedings of 2005 World Congress of the Econometric Society, Cambridge University Press, Cambridge.  p357