M ar 1 99 7 ON THE CARDINALITY AND WEIGHT SPECTRA OF COMPACT SPACES , II
نویسنده
چکیده
Let B(κ, λ) be the subalgebra of P(κ) generated by [κ]. It is shown that if B is any homomorphic image of B(κ, λ) then either |B| < 2 or |B| = |B|, moreover if X is the Stone space of B then either |X| ≤ 2 λ or |X| = |B| = |B|. This implies the existence of 0-dimensional compact T2 spaces whose cardinality and weight spectra omit lots of singular cardinals of “small” cofinality.
منابع مشابه
Approximate Generalized Matching: $f$-Factors and $f$-Edge Covers
In this paper we present linear time approximation schemes for several generalized matching problems on nonbipartite graphs. Our results include O (m)-time algorithms for (1 − )maximum weight f -factor and (1+ )-approximate minimum weight f -edge cover. As a byproduct, we also obtain direct algorithms for the exact cardinality versions of these problems running in O(m √ f(V )) time. The technic...
متن کاملFinitely generated connected locally compact groups
Hofmann and Morris [6] proved that a locally compact connected group G has a finite subset generating a dense subgroup if and only if the weight w(G) of G does not exceed c , the cardinality of the continuum. The minimum cardinality of such a topological generating set is an invariant of the group, is denoted by σ(G), and is called the topological rank of G . For compact abelian groups of weigh...
متن کاملec 2 00 5 SPECTRAL APPROACH TO LINEAR PROGRAMMING BOUNDS ON CODES
We give new proofs of asymptotic upper bounds of coding theory obtained within the frame of Delsarte's linear programming method. The proofs rely on the analysis of eigenvectors of some finite-dimensional operators related to orthogonal polynomials. The examples of the method considered in the paper include binary codes, binary constant-weight codes, spherical codes, and codes in the projective...
متن کاملD ec 1 99 5 A ZFC Dowker space in א ω + 1 : an application of pcf theory to topology
The existence of a Dowker space of cardinality אω+1 and weight אω+1 is proved in ZFC using pcf theory.
متن کاملar X iv : 0 90 1 . 08 58 v 2 [ cs . D M ] 1 3 A ug 2 00 9 Weighted Well - Covered Graphs without Cycles of Length 4 , 6 and 7
A graph is well-covered if every maximal independent set has the same cardinality. The recognition problem of well-covered graphs is known to be co-NP-complete. Let w be a weight function defined on the vertices of G. Then G is w-well-covered if all maximal independent sets of G are of the same weight. The set of weight functions w for which a graph is w-well-covered is a vector space. We prove...
متن کامل