scholarly journals Uniqueness of means in the Cohen model

2019 ◽  
Vol 60 (1) ◽  
pp. 49-60
Author(s):  
 Kalajdzievski Damjan ◽  
Steprāns Juris
Keyword(s):  
1991 ◽  
Vol 56 (2) ◽  
pp. 753-755
Author(s):  
Judith Roitman

1995 ◽  
Vol 60 (3) ◽  
pp. 879-891 ◽  
Author(s):  
Thomas E. Leathrum

AbstractThe collection of branches (maximal linearly ordered sets of nodes) of the tree <ωω (ordered by inclusion) forms an almost disjoint family (of sets of nodes). This family is not maximal — for example, any level of the tree is almost disjoint from all of the branches. How many sets must be added to the family of branches to make it maximal? This question leads to a series of definitions and results: a set of nodes is off-branch if it is almost disjoint from every branch in the tree; an off-branch family is an almost disjoint family of off-branch sets; and is the minimum cardinality of a maximal off-branch family.Results concerning include: (in ZFC) , and (consistent with ZFC) is not equal to any of the standard small cardinal invariants or = 2ω. Most of these consistency results use standard forcing notions—for example, in the Cohen model.Many interesting open questions remain, though—for example, whether .


1990 ◽  
Vol 55 (1) ◽  
pp. 277-283 ◽  
Author(s):  
Labib Haddad ◽  
Marianne Morillon

AbstractWe show that the following property (LN) holds in the basic Cohen model as sketched by Jech: The order topology of any linearly ordered set is normal. This proves the independence of the axiom of choice from LN in ZF, and thus settles a question raised by G. Birkhoff (1940) which was partly answered by van Douwen (1985).


1971 ◽  
Vol 36 (1) ◽  
pp. 28-38 ◽  
Author(s):  
David Pincus

The notion of “support” was introduced by Mostowski in [4] in order to prove that a certain universe satisfied the ordering principle but not the axiom of choice. The notion was refined in [3] and in [1] it was shown to be satisfied in a certain Cohen model of full ZF set theory. This paper is an axiomatic study of universes whose undefined relations are ∈ and a “support structure”, T.In §2 the general theory is introduced and the universes of [4] and [1] are characterized. §3 examines a more complicated universe which will be used in [5] to show that in many cases a consistency in full ZF set theory may be proven directly by the methods of [4]. The embedding theorems of §4 are crucial to this application.


2001 ◽  
Vol 79 (5) ◽  
pp. 801-811 ◽  
Author(s):  
W Glaz ◽  
G C Tabisz

By comparing three model spectral profiles to precise line shapes obtained from quantum calculations, we assess the suitability of the various models for describing the far wings of translational collision-induced spectra. A profile obtained based on a generalized Langevin approach can give a better fit to the quantum shape than the widely used Birnbaum–Cohen model; the fit given by the six-parameter extended Birnbaum–Cohen profile proves to be the best of all three functions. PACS No.: 32.70Jz


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