E. Berlekamp :
“The economist’s view of combinatorial games ,”
pp. 365–405
in
More games of no chance
(Berkeley, CA, 11–21 July 2000 ).
Edited by R. J. Nowakowski .
MSRI Publications 29 .
Cambridge University Press ,
1996 .
MR
1427978
Zbl
0872.90131
incollection
Abstract
People
BibTeX
We introduce two equivalent methodologies for defining and computing a position’s mean (value of playing Black rather than White) and temperature (value of next move). Both methodologies apply in more generality than the classical one. The first, following the notion of a free market, relies on the transfer of a “tax” between players, determined by continuous competitive auctions. The second relies on a generalized thermograph , which reduces to the classical thermograph when the game is loop-free.
When a sum of games is played optimally according the economic rules described, the mean (which is additive) and the temperature determine the final score precisely.
This framework extends and refines several classical notions. Thus, finite games that are numbers in Conway’s sense are now seen to have negative natural temperatures. All games can now be viewed as terminating naturally with integer scores when the temperature reaches \( -1 \) .
@incollection {key1427978m,
AUTHOR = {Berlekamp, Elwyn},
TITLE = {The economist's view of combinatorial
games},
BOOKTITLE = {More games of no chance},
EDITOR = {Nowakowski, Richard J.},
SERIES = {MSRI Publications},
NUMBER = {29},
PUBLISHER = {Cambridge University Press},
YEAR = {1996},
PAGES = {365--405},
NOTE = {(Berkeley, CA, 11--21 July 2000). MR:1427978.
Zbl:0872.90131.},
ISSN = {0940-4740},
ISBN = {9780521646529},
}
E. Berlekamp and Y. Kim :
“Where is the ‘thousand-dollar ko’? ,”
pp. 203–226
in
More games of no chance
(Berkeley, CA, 11–21 July 2000 ).
Edited by R. J. Nowakowski .
MSRI Publications 29 .
Cambridge University Press ,
1996 .
An earlier version of this was published in Go World 71 (1994) .
MR
1427966
Zbl
0873.90141
incollection
Abstract
People
BibTeX
This paper features a problem that was composed to illustrate the power of combinatorial game theory applied to Go endgame positions.
The problem is the sum of many subproblems, over a dozen of which have temperatures significantly greater than one. One of the subproblems is a conspicuous four-point ko, and there are several overlaps among other subproblems. Even though the theory of such positions is far from complete, the paper demonstrates that enough mathematics is now known to obtain provably correct, counterintuitive, solutions to some very difficult Go endgame problems.
@incollection {key1427966m,
AUTHOR = {Berlekamp, Elwyn and Kim, Yonghoan},
TITLE = {Where is the ``thousand-dollar ko''?},
BOOKTITLE = {More games of no chance},
EDITOR = {Nowakowski, Richard J.},
SERIES = {MSRI Publications},
NUMBER = {29},
PUBLISHER = {Cambridge University Press},
YEAR = {1996},
PAGES = {203--226},
NOTE = {(Berkeley, CA, 11--21 July 2000). An
earlier version of this was published
in \textit{Go World} \textbf{71} (1994).
MR:1427966. Zbl:0873.90141.},
ISSN = {0940-4740},
ISBN = {9780521646529},
}
E. Berlekamp :
“The 4G4G4G4G4 problems and solutions ,”
pp. 231–241
in
More games of no chance
(Berkeley, CA, 24–28 July 2000 ).
Edited by R. J. Nowakowski .
MSRI Publications 42 .
Cambridge University Press ,
2002 .
This is related to an article published in Puzzlers’ tribute: A feast for the mind (2002) .
MR
1973015
Zbl
1062.91522
incollection
Abstract
People
BibTeX
This paper discusses a chess problem, a checkers problem, a Go problem, a Domineering problem, and the sum of all four of these problems. These challenging problems were originally entitled Four Games for Gardner and presented at Gathering for Gardner, IV . The solutions of these problems illustrate the power of extended thermography and the notion of rich environments, the relevance and utility of a broad theory of games which may include kos and other loopy positions, and the robustness of this theory to a variety of interpretations of the rules. It also demonstrates the relevance of this branch of mathematics to the classical board games.
@incollection {key1973015m,
AUTHOR = {Berlekamp, Elwyn},
TITLE = {The 4{G}4{G}4{G}4{G}4 problems and solutions},
BOOKTITLE = {More games of no chance},
EDITOR = {Nowakowski, Richard J.},
SERIES = {MSRI Publications},
NUMBER = {42},
PUBLISHER = {Cambridge University Press},
YEAR = {2002},
PAGES = {231--241},
URL = {http://library.msri.org/books/Book42/files/be4g4g.pdf},
NOTE = {(Berkeley, CA, 24--28 July 2000). This
is related to an article published in
\textit{Puzzlers' tribute: A feast for
the mind} (2002). MR:1973015. Zbl:1062.91522.},
ISSN = {0940-4740},
ISBN = {9780521808323},
}
E. Berlekamp and K. Scott :
“Forcing your opponent to stay in control of a loony dots-and-boxes endgame ,”
pp. 317–330
in
More games of no chance
(Berkeley, CA, 24–28 July 2000 ).
Edited by R. J. Nowakowski .
MSRI Publications 42 .
Cambridge University Press ,
2002 .
MR
1973020
Zbl
1062.91523
incollection
Abstract
People
BibTeX
The traditional children’s pencil-and-paper game called Dots-and-Boxes is a contest to outscore the opponent by completing more boxes. It has long been known that winning strategies for certain types of positions in this game can be copied from the winning strategies for another game called Nimstring, which is played according to similar rules except that the Nimstring loser is whichever player completes the last box. Under certain common but restrictive conditions, one player (Right) achieves his optimal Dots-and-Boxes score, \( v \) , by playing so as to win the Nimstring game. An easily computed lower bound on \( v \) is known as the controlled value, \( cv \) . Previous results asserted that \( v = cv \) if \( cv \geq c/2 \) , where \( c \) is the total number of boxes in the game.
In this paper, we weaken this condition from \( cv \geq c \) to \( cv \geq 10 \) , and show this bound to be best possible.
@incollection {key1973020m,
AUTHOR = {Berlekamp, Elwyn and Scott, Katherine},
TITLE = {Forcing your opponent to stay in control
of a loony dots-and-boxes endgame},
BOOKTITLE = {More games of no chance},
EDITOR = {Nowakowski, Richard J.},
SERIES = {MSRI Publications},
NUMBER = {42},
PUBLISHER = {Cambridge University Press},
YEAR = {2002},
PAGES = {317--330},
URL = {http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.113.2813},
NOTE = {(Berkeley, CA, 24--28 July 2000). MR:1973020.
Zbl:1062.91523.},
ISSN = {0940-4740},
ISBN = {9780521808323},
}
E. Berlekamp :
“Idempotents among partisan games ,”
pp. 3–23
in
More games of no chance
(Berkeley, CA, 24–28 July 2000 ).
Edited by R. J. Nowakowski .
MSRI Publications 42 .
Cambridge University Press ,
2002 .
MR
1973000
Zbl
1047.91521
incollection
Abstract
People
BibTeX
We investigate some interesting extensions of the group of traditional games, \( G \) , to a bigger semi-group, \( S \) , generated by some new elements which are idempotents in the sense that each of them satisfies the equation \( G + G = G \) . We present an addition table for these idempotents, which include the 25-year-old “remote star” and the recent “enriched environments”. Adding an appropriate idempotent into a sum of traditional games can often annihilate the less essential features of a position, and thus simplify the analysis by allowing one to focus on more important attributes.
@incollection {key1973000m,
AUTHOR = {Berlekamp, Elwyn},
TITLE = {Idempotents among partisan games},
BOOKTITLE = {More games of no chance},
EDITOR = {Nowakowski, Richard J.},
SERIES = {MSRI Publications},
NUMBER = {42},
PUBLISHER = {Cambridge University Press},
YEAR = {2002},
PAGES = {3--23},
URL = {http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.171.398},
NOTE = {(Berkeley, CA, 24--28 July 2000). MR:1973000.
Zbl:1047.91521.},
ISSN = {0940-4740},
ISBN = {9780521808323},
}
E. Berlekamp :
“Yellow-brown Hackenbush ,”
pp. 413–418
in
Games of no chance 3
(Banff, AB, June 2005 ).
Edited by M. H. Albert and R. J. Nowakowski .
MSRI Publications 56 .
Cambridge University Press ,
2009 .
Zbl
1192.91048
incollection
People
BibTeX
@incollection {key1192.91048z,
AUTHOR = {Berlekamp, Elwyn},
TITLE = {Yellow-brown {H}ackenbush},
BOOKTITLE = {Games of no chance 3},
EDITOR = {Albert, Michael H. and Nowakowski, Richard
J.},
SERIES = {MSRI Publications},
NUMBER = {56},
PUBLISHER = {Cambridge University Press},
YEAR = {2009},
PAGES = {413--418},
NOTE = {(Banff, AB, June 2005). Zbl:1192.91048.},
ISSN = {0940-4740},
ISBN = {9780521861342},
}