Displaying similar documents to “Borsuk-Sieklucki theorem in cohomological dimension theory”

Universal acyclic resolutions for arbitrary coefficient groups

Michael Levin (2003)

Fundamenta Mathematicae

Similarity:

We prove that for every compactum X and every integer n ≥ 2 there are a compactum Z of dimension ≤ n+1 and a surjective U V n - 1 -map r: Z → X such that for every abelian group G and every integer k ≥ 2 such that d i m G X k n we have d i m G Z k and r is G-acyclic.

On the Separation Dimension of K ω

Yasunao Hattori, Jan van Mill (2013)

Bulletin of the Polish Academy of Sciences. Mathematics

Similarity:

We prove that t r t K ω > ω + 1 , where trt stands for the transfinite extension of Steinke’s separation dimension. This answers a question of Chatyrko and Hattori.

On dimensionally restricted maps

H. Murat Tuncali, Vesko Valov (2002)

Fundamenta Mathematicae

Similarity:

Let f: X → Y be a closed n-dimensional surjective map of metrizable spaces. It is shown that if Y is a C-space, then: (1) the set of all maps g: X → ⁿ with dim(f △ g) = 0 is uniformly dense in C(X,ⁿ); (2) for every 0 ≤ k ≤ n-1 there exists an F σ -subset A k of X such that d i m A k k and the restriction f | ( X A k ) is (n-k-1)-dimensional. These are extensions of theorems by Pasynkov and Toruńczyk, respectively, obtained for finite-dimensional spaces. A generalization of a result due to Dranishnikov and Uspenskij...

The G -graded identities of the Grassmann Algebra

Lucio Centrone (2016)

Archivum Mathematicum

Similarity:

Let G be a finite abelian group with identity element 1 G and L = g G L g be an infinite dimensional G -homogeneous vector space over a field of characteristic 0 . Let E = E ( L ) be the Grassmann algebra generated by L . It follows that E is a G -graded algebra. Let | G | be odd, then we prove that in order to describe any ideal of G -graded identities of E it is sufficient to deal with G ' -grading, where | G ' | | G | , dim F L 1 G ' = and dim F L g ' < if g ' 1 G ' . In the same spirit of the case | G | odd, if | G | is even it is sufficient to study only those G -gradings...

Seeking a network characterization of Corson compacta

Ziqin Feng (2021)

Commentationes Mathematicae Universitatis Carolinae

Similarity:

We say that a collection 𝒜 of subsets of X has property ( C C ) if there is a set D and point-countable collections 𝒞 of closed subsets of X such that for any A 𝒜 there is a finite subcollection of 𝒞 such that A = D . Then we prove that any compact space is Corson if and only if it has a point- σ - ( C C ) base. A characterization of Corson compacta in terms of (strong) point network is also given. This provides an answer to an open question in “A Biased View of Topology as a Tool in Functional Analysis”...

The canonical constructions of connections on total spaces of fibred manifolds

Włodzimierz M. Mikulski (2024)

Archivum Mathematicum

Similarity:

We classify classical linear connections A ( Γ , Λ , Θ ) on the total space Y of a fibred manifold Y M induced in a natural way by the following three objects: a general connection Γ in Y M , a classical linear connection Λ on M and a linear connection Θ in the vertical bundle V Y Y . The main result says that if dim ( M ) 3 and dim ( Y ) - dim ( M ) 3 then the natural operators A under consideration form the 17 dimensional affine space.

Extension properties of Stone-Čech coronas and proper absolute extensors

A. Chigogidze (2013)

Fundamenta Mathematicae

Similarity:

We characterize, in terms of X, the extensional dimension of the Stone-Čech corona βX∖X of a locally compact and Lindelöf space X. The non-Lindelöf case is also settled in terms of extending proper maps with values in I τ L , where L is a finite complex. Further, for a finite complex L, an uncountable cardinal τ and a Z τ -set X in the Tikhonov cube I τ we find a necessary and sufficient condition, in terms of I τ X , for X to be in the class AE([L]). We also introduce a concept of a proper absolute...

Continuous images of Lindelöf p -groups, σ -compact groups, and related results

Aleksander V. Arhangel&#039;skii (2019)

Commentationes Mathematicae Universitatis Carolinae

Similarity:

It is shown that there exists a σ -compact topological group which cannot be represented as a continuous image of a Lindelöf p -group, see Example 2.8. This result is based on an inequality for the cardinality of continuous images of Lindelöf p -groups (Theorem 2.1). A closely related result is Corollary 4.4: if a space Y is a continuous image of a Lindelöf p -group, then there exists a covering γ of Y by dyadic compacta such that | γ | 2 ω . We also show that if a homogeneous compact space Y is...

Maximal non valuation domains in an integral domain

Rahul Kumar, Atul Gaur (2020)

Czechoslovak Mathematical Journal

Similarity:

Let R be a commutative ring with unity. The notion of maximal non valuation domain in an integral domain is introduced and characterized. A proper subring R of an integral domain S is called a maximal non valuation domain in S if R is not a valuation subring of S , and for any ring T such that R T S , T is a valuation subring of S . For a local domain S , the equivalence of an integrally closed maximal non VD in S and a maximal non local subring of S is established. The relation between dim ( R , S ) and...

The cleanness of (symbolic) powers of Stanley-Reisner ideals

Somayeh Bandari, Ali Soleyman Jahan (2017)

Czechoslovak Mathematical Journal

Similarity:

Let Δ be a pure simplicial complex on the vertex set [ n ] = { 1 , ... , n } and I Δ its Stanley-Reisner ideal in the polynomial ring S = K [ x 1 , ... , x n ] . We show that Δ is a matroid (complete intersection) if and only if S / I Δ ( m ) ( S / I Δ m ) is clean for all m and this is equivalent to saying that S / I Δ ( m ) ( S / I Δ m , respectively) is Cohen-Macaulay for all m . By this result, we show that there exists a monomial ideal I with (pretty) cleanness property while S / I m or S / I ( m ) is not (pretty) clean for all integer m 3 . If dim ( Δ ) = 1 , we also prove that S / I Δ ( 2 ) ( S / I Δ 2 ) is clean if and only...

Contracting endomorphisms and dualizing complexes

Saeed Nasseh, Sean Sather-Wagstaff (2015)

Czechoslovak Mathematical Journal

Similarity:

We investigate how one can detect the dualizing property for a chain complex over a commutative local Noetherian ring R . Our focus is on homological properties of contracting endomorphisms of R , e.g., the Frobenius endomorphism when R contains a field of positive characteristic. For instance, in this case, when R is F -finite and C is a semidualizing R -complex, we prove that the following conditions are equivalent: (i) C is a dualizing R -complex; (ii) C 𝐑 Hom R ( n R , C ) for some n > 0 ; (iii) G C -dim n R < and C is derived...

On the continuity of Hausdorff dimension of Julia sets and similarity between the Mandelbrot set and Julia sets

Juan Rivera-Letelier (2001)

Fundamenta Mathematicae

Similarity:

Given d ≥ 2 consider the family of polynomials P c ( z ) = z d + c for c ∈ ℂ. Denote by J c the Julia set of P c and let d = c | J c i s c o n n e c t e d be the connectedness locus; for d = 2 it is called the Mandelbrot set. We study semihyperbolic parameters c d : those for which the critical point 0 is not recurrent by P c and without parabolic cycles. The Hausdorff dimension of J c , denoted by H D ( J c ) , does not depend continuously on c at such c d ; on the other hand the function c H D ( J c ) is analytic in - d . Our first result asserts that there is still some...

A note on the multiplier ideals of monomial ideals

Cheng Gong, Zhongming Tang (2015)

Czechoslovak Mathematical Journal

Similarity:

Let 𝔞 [ x 1 , ... , x n ] be a monomial ideal and 𝒥 ( 𝔞 c ) the multiplier ideal of 𝔞 with coefficient c . Then 𝒥 ( 𝔞 c ) is also a monomial ideal of [ x 1 , ... , x n ] , and the equality 𝒥 ( 𝔞 c ) = 𝔞 implies that 0 < c < n + 1 . We mainly discuss the problem when 𝒥 ( 𝔞 ) = 𝔞 or 𝒥 ( 𝔞 n + 1 - ε ) = 𝔞 for all 0 < ε < 1 . It is proved that if 𝒥 ( 𝔞 ) = 𝔞 then 𝔞 is principal, and if 𝒥 ( 𝔞 n + 1 - ε ) = 𝔞 holds for all 0 < ε < 1 then 𝔞 = ( x 1 , ... , x n ) . One global result is also obtained. Let 𝔞 ˜ be the ideal sheaf on n - 1 associated with 𝔞 . Then it is proved that the equality 𝒥 ( 𝔞 ˜ ) = 𝔞 ˜ implies that 𝔞 ˜ is principal.

Finite-dimensional maps and dendrites with dense sets of end points

Hisao Kato, Eiichi Matsuhashi (2006)

Colloquium Mathematicae

Similarity:

The first author has recently proved that if f: X → Y is a k-dimensional map between compacta and Y is p-dimensional (0 ≤ k, p < ∞), then for each 0 ≤ i ≤ p + k, the set of maps g in the space C ( X , I p + 2 k + 1 - i ) such that the diagonal product f × g : X Y × I p + 2 k + 1 - i is an (i+1)-to-1 map is a dense G δ -subset of C ( X , I p + 2 k + 1 - i ) . In this paper, we prove that if f: X → Y is as above and D j (j = 1,..., k) are superdendrites, then the set of maps h in C ( X , j = 1 k D j × I p + 1 - i ) such that f × h : X Y × ( j = 1 k D j × I p + 1 - i ) is (i+1)-to-1 is a dense G δ -subset of C ( X , j = 1 k D j × I p + 1 - i ) for each 0 ≤ i ≤ p.

Locally functionally countable subalgebra of ( L )

M. Elyasi, A. A. Estaji, M. Robat Sarpoushi (2020)

Archivum Mathematicum

Similarity:

Let L c ( X ) = { f C ( X ) : C f ¯ = X } , where C f is the union of all open subsets U X such that | f ( U ) | 0 . In this paper, we present a pointfree topology version of L c ( X ) , named c ( L ) . We observe that c ( L ) enjoys most of the important properties shared by ( L ) and c ( L ) , where c ( L ) is the pointfree version of all continuous functions of C ( X ) with countable image. The interrelation between ( L ) , c ( L ) , and c ( L ) is examined. We show that L c ( X ) c ( 𝔒 ( X ) ) for any space X . Frames L for which c ( L ) = ( L ) are characterized.