  We discuss the interconnections between AO*, adversarial game-searching
algorithms, e.g., proof number search and minimax search. The former was
developed in the context of a general AND/OR graph model, while the latter were
mostly presented in game-trees which are sometimes modeled using AND/OR trees.
It is thus worth investigating to what extent these algorithms are related and
how they are connected. In this paper, we explicate the interconnections
between these search paradigms. We argue that generalized proof number search
might be regarded as a more informed replacement of AO* for solving arbitrary
AND/OR graphs, and the minimax principle might also extended to use dual
heuristics.
