Reaping Numbers of Boolean Algebras |
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Authors: | Dow, Alan Steprans, Juris Watson, Stephen |
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Affiliation: | Department of Mathematics York University 4700 Keele Street North York Ontario Canada M3J 1P3 |
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Abstract: | A subset A of a Boolean algebra B is said to be (n,m)-reapedif there is a partition of unity p B of size n such that |{b p:b a 0}| m for all a A. The reaping number rn,m (B) ofa Boolean algebra B is the minimum cardinality of a set A B{0}which cannot be (n,m)-reaped. It is shown that for each n, thereis a Boolean algebra B such that rn+1,2(B) rn,2(B). Also, {rn,m(B):mn } consists of at most two consecutive cardinals. The existenceof a Boolean algebra B such that rn,m (B) rn',m' (B) is equivalentto a statement in finite combinatorics which is also discussed. |
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