منابع مشابه
Forcing with Ideals Generated by Closed Sets
Consider the posets PI = Borel(R) \ I where I is a σ-ideal σ-generated by a projective collection of closed sets. Then the PI extension is given by a single real r of an almost minimal degree: every real s ∈ V [r] is Cohen-generic over V or
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In this paper, we show that one can associate a pseudoregulus with every scattered linear set of rank 3n in PG(2n − 1, q3). We construct a scattered linear set having a given pseudoregulus as associated pseudoregulus and prove that there are q − 1 different scattered linear sets that have the same associated pseudoregulus. Finally, we give a characterisation of reguli and pseudoreguli in PG(3, ...
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Let G be a connected graph of order p and let 0 ::f. s ~ V ( G). Then S is a rad(G)-forcing set (or a radius-forcing set of G) if, for each v E V(G), there exists v' E S with dc(v, v') ?: rad(G). The cardinality of a smallest radius-forcing set of G is called the radius-forcing number of G and is denoted by rf(G). A graph G is called a randomly k-forcing graph for a positive integer k if every ...
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We introduce the study of forcing sets in mathematical origami. The origami material folds flat along straight line segments called creases, each of which is assigned a folding direction of mountain or valley. A subset F of creases is forcing if the global folding mountain/valley assignment can be deduced from its restriction to F . In this paper we focus on one particular class of foldable pat...
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and call a set A provident if it is transitive and closed under all p-rud-rec functions with p a member of A. * If ζ is the least ordinal not in a provident set A, then ζ is indecomposable, that is, that the sum of two ordinals less than ζ is less than ζ. Conversely, if ζ is indecomposable, η > ζ and p ∈ Jζ , then the Jensen set Jη is is closed under all p-rud rec functions; in particular Jζ is...
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ژورنال
عنوان ژورنال: Annals of Pure and Applied Logic
سال: 2012
ISSN: 0168-0072
DOI: 10.1016/j.apal.2012.02.004