Game Solving Procedure SSSR is Unsurpassed

Abstract A search procedure X1 for solving minimax game trees surpasses a search procedure X2 if AREA(X1) ⊆AREA(X2) holds for any game tree G, where AREA(X) denotes the set of nodes in G expanded by X. X1 strictly surpasses X2 if X1 surpasses X2 and AREA(X1) ⊂ AREA(X2) holds for at least one game tree, where ⊂ denotes proper inclusion. A search procedure X is unsurpassed if no search procedure strictly surpasses X. In this paper, we prove that a search procedure called H* is unsurpassed.