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Wyszukujesz frazę "indecomposable" wg kryterium: Temat


Wyświetlanie 1-11 z 11
Tytuł:
Free spaces
Autorzy:
Song, Jian
Tymchatyn, E.
Powiązania:
https://bibliotekanauki.pl/articles/1205112.pdf
Data publikacji:
2000
Wydawca:
Polska Akademia Nauk. Instytut Matematyczny PAN
Tematy:
free space
hereditarily indecomposable continuum
polyhedron
Opis:
A space Y is called a free space if for each compactum X the set of maps with hereditarily indecomposable fibers is a dense $G_δ$-subset of C(X,Y), the space of all continuous functions of X to Y. Levin proved that the interval I and the real line ℝ are free. Krasinkiewicz independently proved that each n-dimensional manifold M (n ≥ 1) is free and the product of any space with a free space is free. He also raised a number of questions about the extent of the class of free spaces. In this paper we will answer most of those questions. We prove that each cone is free. We introduce the notion of a locally free space and prove that a locally free ANR is free. It follows that every polyhedron is free. Hence, 1-dimensional Peano continua, Menger manifolds and many hereditarily unicoherent continua are free. We also give examples that show some limits to the extent of the class of free spaces.
Źródło:
Fundamenta Mathematicae; 2000, 163, 3; 229-239
0016-2736
Pojawia się w:
Fundamenta Mathematicae
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Irreducibility of inverse limits on intervals
Autorzy:
Ryden, David
Powiązania:
https://bibliotekanauki.pl/articles/1205022.pdf
Data publikacji:
2000
Wydawca:
Polska Akademia Nauk. Instytut Matematyczny PAN
Tematy:
continuum
irreducible
inverse limit
chainable
triod
unicoherent
indecomposable
absolutely terminal subcontinuum
Opis:
A procedure for obtaining points of irreducibility for an inverse limit on intervals is developed. In connection with this, the following are included. A semiatriodic continuum is defined to be a continuum that contains no triod with interior. Characterizations of semiatriodic and unicoherent continua are given, as well as necessary and sufficient conditions for a subcontinuum of a semiatriodic and unicoherent continuum M to lie within the interior of a proper subcontinuum of M.
Źródło:
Fundamenta Mathematicae; 2000, 165, 1; 29-53
0016-2736
Pojawia się w:
Fundamenta Mathematicae
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Bing maps and finite-dimensional maps
Autorzy:
Levin, Michael
Powiązania:
https://bibliotekanauki.pl/articles/1205475.pdf
Data publikacji:
1996
Wydawca:
Polska Akademia Nauk. Instytut Matematyczny PAN
Tematy:
finite-dimensional maps
hereditarily indecomposable continua
Opis:
Let X and Y be compacta and let f:X → Y be a k-dimensional map. In [5] Pasynkov stated that if Y is finite-dimensional then there exists a map $g : X → \mathbb{I}^k$ such that dim (f × g) = 0. The problem that we deal with in this note is whether or not the restriction on the dimension of Y in the Pasynkov theorem can be omitted. This problem is still open.
 Without assuming that Y is finite-dimensional Sternfeld [6] proved that there exists a map $g : X → \mathbb{I}^k$ such that dim (f × g) = 1. We improve this result of Sternfeld showing that there exists a map $g : X → mathbb{I}^{k+1}$ such that dim (f × g) =0. The last result is generalized to maps f with weakly infinite-dimensional fibers.
 Our proofs are based on so-called Bing maps. A compactum is said to be a Bing compactum if its compact connected subsets are all hereditarily indecomposable, and a map is said to be a Bing map if all its fibers are Bing compacta. Bing maps on finite-dimensional compacta were constructed by Brown [2]. We construct Bing maps for arbitrary compacta. Namely, we prove that for a compactum X the set of all Bing maps from X to $\mathbb{I}$ is a dense $G_δ$-subset of $C(X, \mathbb{I})$.
Źródło:
Fundamenta Mathematicae; 1996, 151, 1; 47-52
0016-2736
Pojawia się w:
Fundamenta Mathematicae
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Hyperspaces of two-dimensional continua
Autorzy:
Levin, Michael
Sternfeld, Yaki
Powiązania:
https://bibliotekanauki.pl/articles/1205496.pdf
Data publikacji:
1996
Wydawca:
Polska Akademia Nauk. Instytut Matematyczny PAN
Tematy:
hyperspaces
hereditarily indecomposable continua
one- and two-dimensional continua
Opis:
Let X be a compact metric space and let C(X) denote the space of subcontinua of X with the Hausdorff metric. It is proved that every two-dimensional continuum X contains, for every n ≥ 1, a one-dimensional subcontinuum $T_n$ with $dim C (T_n) ≥ n$. This implies that X contains a compact one-dimensional subset T with dim C (T) = ∞.
Źródło:
Fundamenta Mathematicae; 1996, 150, 1; 17-24
0016-2736
Pojawia się w:
Fundamenta Mathematicae
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Chaotic continua of (continuum-wise) expansive homeomorphisms and chaos in the sense of Li and Yorke
Autorzy:
Kato, Hisao
Powiązania:
https://bibliotekanauki.pl/articles/1208450.pdf
Data publikacji:
1994
Wydawca:
Polska Akademia Nauk. Instytut Matematyczny PAN
Tematy:
expansive homeomorphism
continuum-wise expansive homeomorphism
stable and unstable sets
scrambled set
chaotic in the sense of Li and Yorke
independent
indecomposable continuum
Opis:
A homeomorphism f : X → X of a compactum X is expansive (resp. continuum-wise expansive) if there is c > 0 such that if x, y ∈ X and x ≠ y (resp. if A is a nondegenerate subcontinuum of X), then there is n ∈ ℤ such that $d(f^n(x), f^n(y)) > c$ (resp. $diam f^n(A) > c$). We prove the following theorem: If f is a continuum-wise expansive homeomorphism of a compactum X and the covering dimension of X is positive (dim X > 0), then there exists a σ-chaotic continuum Z = Z(σ) of f (σ = s or σ = u), i.e. Z is a nondegenerate subcontinuum of X satisfying: (i) for each x ∈ Z, $V^σ(x; Z)$ is dense in Z, and (ii) there exists τ > 0 such that for each x ∈ Z and each neighborhood U of x in X, there is y ∈ U ∩ Z such that $lim inf_{n → ∞} d(f^n(x), f^n(y))$ ≥ τ if σ = s, and $lim inf_{n → ∞} d(f^{-n}(x), f^{-n}(y))$ ≥ τ if σ = u; in particular, $W^σ(x) ≠ W^σ(y)$. Here
  $V^s(x; Z) = {z ∈ Z|$ there is a subcontinuum A of Z such that
      x, z ∈ A and $lim_{n → ∞} diam f^n(A) = 0}$,
$V^u(x; Z) = {z ∈ Z| there is a subcontinuum A of Z such that
      x, z ∈ A and $lim_{n → ∞} diam f^{-n}(A) = 0}$,
   $W^s(x) = {x' ∈ X|$ $lim_{n → ∞} d(f^n(x), f^n(x')) = 0}$, and
   $W^u(x) = {x' ∈ X|$ $lim_{n → ∞} d(f^{-n}(x), f^{-n}(x'))=0}$.
As a corollary, if f is a continuum-wise expansive homeomorphism of a compactum X with dim X > 0 and Z is a σ-chaotic continuum of f, then for almost all Cantor sets C ⊂ Z, f or $f^{-1}$ is chaotic on C in the sense of Li and Yorke according as σ = s or u). Also, we prove that if f is a continuum-wise expansive homeomorphism of a compactum X with dim X > 0 and there is a finite family $\mathbb{F}$ of graphs such that X is $\mathbb{F}$-like, then each chaotic continuum of f is indecomposable. Note that every expansive homeomorphism is continuum-wise expansive.
Źródło:
Fundamenta Mathematicae; 1994, 145, 3; 261-279
0016-2736
Pojawia się w:
Fundamenta Mathematicae
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On indecomposability and composants of chaotic continua
Autorzy:
Kato, Hisao
Powiązania:
https://bibliotekanauki.pl/articles/1205482.pdf
Data publikacji:
1996
Wydawca:
Polska Akademia Nauk. Instytut Matematyczny PAN
Tematy:
expansive homeomorphism
continuum-wise expansive homeomorphism
indecomposable
composant
chaotic continuum
plane compactum
stable and unstable sets
Opis:
A homeomorphism f:X → X of a compactum X with metric d is expansive if there is c > 0 such that if x,y ∈ X and x ≠ y, then there is an integer n ∈ ℤ such that $d(f^n(x),f^n(y)) > c$. A homeomorphism f: X → X is continuum-wise expansive if there is c > 0 such that if A is a nondegenerate subcontinuum of X, then there is an integer n ∈ ℤ such that $diami f^n(A) > c$. Clearly, every expansive homeomorphism is continuum-wise expansive, but the converse assertion is not true. In [6], we defined the notion of chaotic continua of homeomorphisms and proved the existence of chaotic continua of continuum-wise expansive homeomorphisms. Also, we studied indecomposability of chaotic continua. In this paper, we investigate further more properties of indecomposability of chaotic continua and their composants. In particular, we prove that if f:X → X is a continuum-wise expansive homeomorphism of a plane compactum $X ⊂ ℝ^2$ with dim X > 0, then there exists a σ-chaotic continuum Z (σ = s or u) of f such that Z is an indecomposable subcontinuum of X and for each z ∈ Z the composant c(z) of Z containing z coincides with the continuum-wise σ-stable set $V^σ(z;Z)$.
Źródło:
Fundamenta Mathematicae; 1996, 150, 3; 245-253
0016-2736
Pojawia się w:
Fundamenta Mathematicae
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Algorithm and program for finding minimal and quasi-minimal cuts in graphs
Algorytm i program znajdowania minimalnych i quasi-minimalnych przekrojów grafu
Autorzy:
Grishkeyich, A.
Piątek, Ł.
Powiązania:
https://bibliotekanauki.pl/articles/268053.pdf
Data publikacji:
2008
Wydawca:
Politechnika Gdańska. Wydział Elektrotechniki i Automatyki
Tematy:
krata dystrybutywna
przekrój nierozkladalny
jeden, dwu, trzy elementowy przekrój
distributive lattice
indecomposable cut
one-, two-, three- elements cut
Opis:
It was found, that the set of minimum cuts, separating two chosen vertices in graph, have the structure of distributive lattice. It was developed an effective procedure for finding the set of 1, 2 and 3 elements cuts in graph based on the consideration of distributive lattice of the set of minimum cuts. The procedure consists of first, the algorithm for finding indecomposable minimal cuts of distributive lattice. Second, algorithm for synthesis, using resulting subset from stage one, of the entire set of minimum cuts. The third, is the algorithm for describing the set of quasi-minimum (close to the minimum, next to minimum) cuts in the form of sum of distributive lattices of minimal cuts found for the modified function of weight. The computer program, implementing these algorithms, is presented with examples.
Ustalono, że zbiór minimalnych przekrojów, rozdzielających dwa zadane wierzchołki grafu, z wprowadzonymi na i operacjami ma strukturę kraty dystrybutywnej. Opracowano skuteczną algorytmiczną procedurę znajdowania zbioru jed dwu i trzy elementowych przekrojów grafu bazującą na rozpatrzeniu dystrybutywnych krat zbioru minimalnych przekrojów grafu. Procedura składa się z, po pierwsze, algorytmu szukania nierozkładalnych minimalnych przekrojów Dystrybutywnej, po drugie, algorytmu syntezy po tym podzbiorze w kracie dystrybutywnej całego poszukiwanego zbioru minimalnych przekrojów i, po trzecie, algorytmu opisu zbioru quasi-minimalnych (bliskich do minimalnych, następnych po minimalnych) przekrojów w formie sumy krat dystrybutywnych minimalnych przekrojów, znalezionych dla zmodyfikowanej funkcji wagi. Przedstawiono zrealizowany program komputerowy i przedstawiono przykłady pracy programu.
Źródło:
Zeszyty Naukowe Wydziału Elektrotechniki i Automatyki Politechniki Gdańskiej; 2008, 25; 49-52
1425-5766
2353-1290
Pojawia się w:
Zeszyty Naukowe Wydziału Elektrotechniki i Automatyki Politechniki Gdańskiej
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Open maps between Knaster continua
Autorzy:
Eberhart, Carl
Fugate, J.
Schumann, Shannon
Powiązania:
https://bibliotekanauki.pl/articles/1205180.pdf
Data publikacji:
1999
Wydawca:
Polska Akademia Nauk. Instytut Matematyczny PAN
Tematy:
continuum
degree
indecomposable
(induced) open mapping
semigroup
approximating sequence
Opis:
We investigate the set of open maps from one Knaster continuum to another. A structure theorem for the semigroup of open induced maps on a Knaster continuum is obtained. Homeomorphisms which are not induced are constructed, and it is shown that the induced open maps are dense in the space of open maps between two Knaster continua. Results about the structure of the semigroup of open maps on a Knaster continuum are obtained and two questions about the structure are posed.
Źródło:
Fundamenta Mathematicae; 1999, 162, 2; 119-148
0016-2736
Pojawia się w:
Fundamenta Mathematicae
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Decomposition tree and indecomposable coverings
Autorzy:
Breiner, Andrew
Deogun, Jitender
Ille, Pierre
Powiązania:
https://bibliotekanauki.pl/articles/744120.pdf
Data publikacji:
2011
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
interval
indecomposable
k-covering
decomposition tree
Opis:
Let G = (V,A) be a directed graph. With any subset X of V is associated the directed subgraph G[X] = (X,A ∩ (X×X)) of G induced by X. A subset X of V is an interval of G provided that for a,b ∈ X and x ∈ V∖X, (a,x) ∈ A if and only if (b,x) ∈ A, and similarly for (x,a) and (x,b). For example ∅, V, and {x}, where x ∈ V, are intervals of G which are the trivial intervals. A directed graph is indecomposable if all its intervals are trivial. Given an integer k > 0, a directed graph G = (V,A) is called an indecomposable k-covering provided that for every subset X of V with |X| ≤ k, there exists a subset Y of V such that X ⊆ Y, G[Y] is indecomposable with |Y| ≥ 3. In this paper, the indecomposable k-covering directed graphs are characterized for any k > 0.
Źródło:
Discussiones Mathematicae Graph Theory; 2011, 31, 1; 37-44
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The structure of atoms (hereditarily indecomposable continua)
Autorzy:
Ball, R.
Hagler, J.
Sternfeld, Yaki
Powiązania:
https://bibliotekanauki.pl/articles/1205357.pdf
Data publikacji:
1998
Wydawca:
Polska Akademia Nauk. Instytut Matematyczny PAN
Tematy:
atoms (hereditarily indecomposable continua)
ultrametric spaces
isometries
lattices
lattice isomorphism
Opis:
Let X be an atom (= hereditarily indecomposable continuum). Define a metric ϱ on X by letting $ϱ(x,y) = W(A_{xy})$ where $A_{x,y}$ is the (unique) minimal subcontinuum of X which contains x and y and W is a Whitney map on the set of subcontinua of X with W(X) = 1. We prove that ϱ is an ultrametric and the topology of (X,ϱ) is stronger than the original topology of X. The ϱ-closed balls C(x,r) = {y ∈ X:ϱ ( x,y) ≤ r} coincide with the subcontinua of X. (C(x,r) is the unique subcontinuum of X which contains x and has Whitney value r.) It is proved that for any two (nontrivial) atoms and any Whitney maps on them, the corresponding ultrametric spaces are isometric. This implies in particular that the combinatorial structure of subcontinua is identical in all atoms. The set M(X) of all monotone upper semicontinuous decompositions of X is a lattice when ordered by refinement. It is proved that for two atoms X and Y, M(X) is lattice isomorphic to M(Y) if and only if X is homeomorphic to Y.
Źródło:
Fundamenta Mathematicae; 1998, 156, 3; 261-278
0016-2736
Pojawia się w:
Fundamenta Mathematicae
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Statistical estimation of higher-order spectral densities by means of general tapering
Autorzy:
Baba Harra, M'hammed
Powiązania:
https://bibliotekanauki.pl/articles/1339110.pdf
Data publikacji:
1997
Wydawca:
Polska Akademia Nauk. Instytut Matematyczny PAN
Tematy:
shift-in-time
higher-order spectral densities
cumulant
admissible values
indecomposable partitions
stochastic processes
product moment
tapering
characteristic number
Opis:
Given a realization on a finite interval of a continuous-time stationary process, we construct estimators for higher order spectral densities. Tapering and shift-in-time methods are used to build estimators which are asymptotically unbiased and consistent for all admissible values of the argument. Asymptotic results for the fourth-order densities are given. Detailed attention is paid to the nth order case.
Źródło:
Applicationes Mathematicae; 1996-1997, 24, 4; 357-381
1233-7234
Pojawia się w:
Applicationes Mathematicae
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-11 z 11

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