题目：Simplifying Extensive Games and Invariance of Equilibrium
It is important to understand the effect of small structural changes in dynamic games on equilibrium behavior. To facilitate, I recast Elmes and Reny's (1994) invariance operations of Coalescing and Adding into Conflating and Duplicating which, together with the Simultanizing operation from Battigalli et al. (2020), provide a new characterization of normal form equivalence. Equilibrium behavioral is often invariant to simplification of dynamic games as well. Similar to Battigalli et al.'s (2020) analysis of behavioral equivalence, I discern between behavioral simplification and normal form simplification and show that both can be characterized by adding the Pruning operation to the characterizations of their corresponding equivalence relation. Examples are provided based on the obviousness refinement of weak dominance (Li, 2017).