@article {IOPORT.05013300,
    author       = {Hayward, Ryan and Bj\"ornsson, Yngvi and Johanson, Michael and Kan, Morgan and Po, Nathan and van Rijswijck, Jack},
    title        = {Solving $7\times 7$ hex with domination, fill-in, and virtual connections.},
    year         = {2005},
    journal      = {Theoretical Computer Science},
    volume       = {349},
    number       = {2},
    issn         = {0304-3975},
    pages        = {123-139},
    publisher    = {Elsevier Science Publishers, Amsterdam},
    doi          = {10.1016/j.tcs.2005.09.042},
    abstract     = {Summary: We present an algorithm that determines the outcome of an arbitrary Hex game-state by finding a winning virtual connection for the winning player. Our algorithm recursively searches the game-tree, combining fixed and dynamic game-state virtual connection composition rules to find a winning virtual connection for one of the two players. The search is enhanced by pruning the game-tree according to two new Hex game-state reduction results: under certain conditions, (i) some moves dominate others, and (ii) some board-cells can be ``filled-in'' without changing the game's outcome. The algorithm is powerful enough to solve arbitrary $7\times 7$ game-states. In particular, we use it to determine the outcome of a $7\times 7$ Hex game after each of the 49 possible opening moves, in each case finding an explicit proof-tree for the winning player.},
    identifier   = {05013300},
}