Results 301 to 310 of about 6,858,530 (350)

Numerical representation of intransitive preferences on a countable set

Journal of Economic Theory, 1983
D. Bridges
semanticscholar   +3 more sources

The Potts model on Zd with countable set of spin values

Journal of Mathematical Physics, 2004
N. Ganikhodjaev
semanticscholar   +3 more sources

COUNTABLY COMPACT L-SETS

International Journal of Uncertainty, Fuzziness and Knowledge-Based Systems, 2004
In this paper, the concepts of countable presemi-compactness and presemi-Lindelof property in L-topological spaces are introduced. They are defined for arbitrary L-subsets, and some of their characteristic properties and fundamental properties are studied.
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The Theory of Countable Borel Equivalence Relations

The theory of definable equivalence relations has been a vibrant area of research in descriptive set theory for the past three decades. It serves as a foundation of a theory of complexity of classification problems in mathematics and is further motivated
A. Kechris
semanticscholar   +1 more source

Countable and Uncountable Sets

2011
We have already come across several infinite sets: N the set of naturals, Z the set of integers, Q the set of rationals, and R the set of reals. It turns out that, in some sense to be made precise, the first three sets may be said to have the same cardinality, while the last one has a strictly larger cardinality.
Ulrich Daepp, Pamela Gorkin
openaire   +2 more sources

Generating Countable Sets of Permutations

Journal of the London Mathematical Society, 1995
Let \(E\) be an infinite set and let \(\text{Sym}(E)\) denote the symmetric permutation group of \(E\). It is shown that every countable subset of \(\text{Sym}(E)\) is contained in a 2-generator subgroup of \(\text{Sym}(E)\), answering a question of Wagon in the affirmative.
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Countable dense sets of dendrites

Topology and its Applications, 2023
In this paper the authors study the countable dense homogeneity degree which is analogous to the homogeneity degree of a topological space. They present a full characterization of the countable homogeneity degree for the class of dendrites. They show for example that for a dendrite, the degree is finite iff it is a tree.
García-Becerra, Rafael E., López, María de J., Pellicer-Covarrubias, Patricia   +2 more
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Spaces in Which Countable Closed Sets Have Countable Character

Acta Mathematica Hungarica, 2000
A topological space \(X\) is called a \(CC_\omega\)-space if every countable closed subset of \(X\) has countable character. It is proved that a \(T_3\)-space \(X\) is a \(CC_\omega\)-space if and only if the set of limit points of \(X\) is countably compact and every compact subset has countable character. It is also shown that among \(T_3\)-spaces, \(
openaire   +1 more source

Countable models of set theories

1973
H. Friedman
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On hereditarily countable sets

Journal of Symbolic Logic, 1982
AbstractIt is shown (in ZF) that every hereditarily countable set has rank less than ω2, and that if ℵ1 is singular then there are hereditarily countable sets of all ranks less than ω2.
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