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Discrepancy Game
A discrepancy game is a kind of positional game. Like most positional games, it is described by its set of ''positions/points/elements'' (X) and a family of ''sets'' (\mathcal- a family of subsets of X). It is played by two players, called ''Balancer'' and ''Unbalancer''. Each player in turn picks an element. The goal of Balancer is to ensure that every set in \mathcal is balanced, i.e., the elements in each set are distributed roughly equally between the players. The goal of Unbalancer is to ensure that at least one set is unbalanced. Formally, the goal of balancer is defined by a vector (b_1,\ldots,b_n) where ''n'' is the number of sets in \mathcal. Balancer wins if in every set ''i'', the difference between the number of elements taken by Balancer and the number of elements taken by Unbalancer is at most ''bi''. Equivalently, we can think of Balancer as labeling each element with +1 and Unbalancer labeling each element with -1, and Balancer's goal is to ensure the absolute ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Positional Game
A positional game is a kind of a combinatorial game for two players. It is described by: *Xa finite set of elements. Often ''X'' is called the ''board'' and its elements are called ''positions''. *\mathcala family of subsets of X. These subsets are usually called the ''winning-sets''. * A criterion for winning the game. During the game, players alternately claim previously-unclaimed positions, until one of the players wins. If all positions in X are taken while no player wins, the game is considered a draw. The classic example of a positional game is Tic-tac-toe. In it, X contains the 9 squares of the game-board, \mathcal contains the 8 lines that determine a victory (3 horizontal, 3 vertical and 2 diagonal), and the winning criterion is: the first player who holds an entire winning-set wins. Other examples of positional games are Hex and the Shannon switching game. For every positional game there are exactly three options: either the first player has a winning strategy, or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Family Of Sets
In set theory and related branches of mathematics, a collection F of subsets of a given set S is called a family of subsets of S, or a family of sets over S. More generally, a collection of any sets whatsoever is called a family of sets, set family, or a set system. The term "collection" is used here because, in some contexts, a family of sets may be allowed to contain repeated copies of any given member, and in other contexts it may form a proper class rather than a set. A finite family of subsets of a finite set S is also called a ''hypergraph''. The subject of extremal set theory concerns the largest and smallest examples of families of sets satisfying certain restrictions. Examples The set of all subsets of a given set S is called the power set of S and is denoted by \wp(S). The power set \wp(S) of a given set S is a family of sets over S. A subset of S having k elements is called a k-subset of S. The k-subsets S^ of a set S form a family of sets. Let S = \. An ex ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Maker-Breaker Game
A Maker-Breaker game is a kind of positional game. Like most positional games, it is described by its set of ''positions/points/elements'' (X) and its family of ''winning-sets'' (\mathcal- a family of subsets of X). It is played by two players, called Maker and Breaker, who alternately take previously-untaken elements. In a Maker-Breaker game, Maker wins if he manages to hold all the elements of a winning-set, while Breaker wins if he manages to prevent this, i.e. to hold at least one element in each winning-set. Draws are not possible. In each Maker-Breaker game, either Maker or Breaker has a winning strategy. The main research question about these games is which of these two options holds. Examples A classic Maker-Breaker game is Hex. There, the winning-sets are all paths from the left side of the board to the right side. Maker wins by owning a connected path; Breaker wins by owning a connected path from top to bottom, since it blocks all connected paths from left to right. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |