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Wyszukujesz frazę "homomorphism" wg kryterium: Temat


Tytuł:
Distinguishing graphs by the number of homomorphisms
Autorzy:
Fisk, Steve
Powiązania:
https://bibliotekanauki.pl/articles/971917.pdf
Data publikacji:
1995
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
graph homomorphism
chromatic number
Opis:
A homomorphism from one graph to another is a map that sends vertices to vertices and edges to edges. We denote the number of homomorphisms from G to H by |G → H|. If is a collection of graphs, we say that distinguishes graphs G and H if there is some member X of such that |G → X | ≠ |H → X|. is a distinguishing family if it distinguishes all pairs of graphs.
We show that various collections of graphs are a distinguishing family.
Źródło:
Discussiones Mathematicae Graph Theory; 1995, 15, 1; 73-75
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On maximal finite antichains in the homomorphism order of directed graphs
Autorzy:
Nesetril, Jaroslav
Tardif, Claude
Powiązania:
https://bibliotekanauki.pl/articles/743175.pdf
Data publikacji:
2003
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
chromatic number
homomorphism duality
Opis:
We show that the pairs ${T,D_T}$ where T is a tree and $D_T$ its dual are the only maximal antichains of size 2 in the category of directed graphs endowed with its natural homomorphism ordering.
Źródło:
Discussiones Mathematicae Graph Theory; 2003, 23, 2; 325-332
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Cryptography with right-angled Artin groups
Autorzy:
Flores, R.
Kahrobaei, D.
Powiązania:
https://bibliotekanauki.pl/articles/375820.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
authentication schemes
group homomorphism
graph homomorphism
schematy uwierzytelniania
homomorfizm grup
homeomorfizm grafów
Opis:
In this paper we propose right-angled Artin groups as a platform for secret sharing schemes based on the efficiency (linear time) of the word problem. Inspired by previous work of Grigoriev-Shpilrain in the context of graphs, we define two new problems: Subgroup Isomorphism Problem and Group Homomorphism Problem. Based on them, we also propose two new authentication schemes. For right-angled Artin groups, the Group Homomorphism and Graph Homomorphism problems are equivalent, and the later is known to be NP-complete. In the case of the Subgroup Isomorphism problem, we bring some results due to Bridson who shows there are right-angled Artin groups in which this problem is unsolvable.
Źródło:
Theoretical and Applied Informatics; 2016, 28, 3; 8-16
1896-5334
Pojawia się w:
Theoretical and Applied Informatics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Algebraic characterization of finite (branched) coverings
Autorzy:
Mulero, M.
Powiązania:
https://bibliotekanauki.pl/articles/1205293.pdf
Data publikacji:
1998
Wydawca:
Polska Akademia Nauk. Instytut Matematyczny PAN
Tematy:
branched covering
open and closed map
ring of continuous functions
flat homomorphism
integral homomorphism
Opis:
Every continuous map X → S defines, by composition, a homomorphism between the corresponding algebras of real-valued continuous functions C(S) → C(X). This paper deals with algebraic properties of the homomorphism C(S) → C(X) in relation to topological properties of the map X → S. The main result of the paper states that a continuous map X → S between topological manifolds is a finite (branched) covering, i.e., an open and closed map whose fibres are finite, if and only if the induced homomorphism C(S) → C(X) is integral and flat.
Źródło:
Fundamenta Mathematicae; 1998, 158, 2; 165-180
0016-2736
Pojawia się w:
Fundamenta Mathematicae
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Partial covers of graphs
Autorzy:
Fiala, Jirí
Kratochvíl, Jan
Powiązania:
https://bibliotekanauki.pl/articles/743545.pdf
Data publikacji:
2002
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
covering projection
computational complexity
graph homomorphism
Opis:
Given graphs G and H, a mapping f:V(G) → V(H) is a homomorphism if (f(u),f(v)) is an edge of H for every edge (u,v) of G. In this paper, we initiate the study of computational complexity of locally injective homomorphisms called partial covers of graphs. We motivate the study of partial covers by showing a correspondence to generalized (2,1)-colorings of graphs, the notion stemming from a practical problem of assigning frequencies to transmitters without interference. We compare the problems of deciding existence of partial covers and of full covers (locally bijective homomorphisms), which were previously studied.
Źródło:
Discussiones Mathematicae Graph Theory; 2002, 22, 1; 89-99
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Some properties of pseudo-BCI algebras
Autorzy:
Dymek, Grzegorz
Powiązania:
https://bibliotekanauki.pl/articles/962850.pdf
Data publikacji:
2018
Wydawca:
Polskie Towarzystwo Matematyczne
Tematy:
Pseudo-BCI algebra
deductive system
homomorphism
Opis:
In this paper the notion of an essential closed deductive system of a pseudo-BCI algebra is defined and investigated. Among other things, it is proved that such a deductive system contains all coatoms of the pseudo-BCI algebra. Also, the notions of homomorphisms and semihomomorphisms of pseudo-BCI algebras are studied and some of their properties are presented.
Źródło:
Commentationes Mathematicae; 2018, 58, 1-2; 19-35
0373-8299
Pojawia się w:
Commentationes Mathematicae
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The set of automorphisms of B(H) is topologically reflexive in B(B(H))
Autorzy:
Molnár, Lajos
Powiązania:
https://bibliotekanauki.pl/articles/1220333.pdf
Data publikacji:
1997
Wydawca:
Polska Akademia Nauk. Instytut Matematyczny PAN
Tematy:
reflexivity
automorphism
Jordan homomorphism
automatic surjectivity
Opis:
The aim of this paper is to prove the statement announced in the title which can be reformulated in the following way. Let H be a separable infinite-dimensional Hilbert space and let Φ: B(H) → B(H) be a continuous linear mapping with the property that for every A ∈ B(H) there exists a sequence $(Φ_n)$ of automorphisms of B(H) (depending on A) such that $Φ(A)= lim_n Φ_n(A)$. Then Φ is an automorphism. Moreover, a similar statement holds for the set of all surjective isometries of B(H).
Źródło:
Studia Mathematica; 1997, 122, 2; 183-193
0039-3223
Pojawia się w:
Studia Mathematica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Families of strongly projective graphs
Autorzy:
Larose, Benoit
Powiązania:
https://bibliotekanauki.pl/articles/743360.pdf
Data publikacji:
2002
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
distance-transitive graphs
graph homomorphism
graph product
Opis:
We give several characterisations of strongly projective graphs which generalise in many respects odd cycles and complete graphs [7]. We prove that all known families of projective graphs contain only strongly projective graphs, including complete graphs, odd cycles, Kneser graphs and non-bipartite distance-transitive graphs of diameter d ≥ 3.
Źródło:
Discussiones Mathematicae Graph Theory; 2002, 22, 2; 271-292
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Allegory of Isomorphism
Autorzy:
Isaac, Alistair M. C.
Powiązania:
https://bibliotekanauki.pl/articles/2200243.pdf
Data publikacji:
2019
Wydawca:
Projekt Avant
Tematy:
representation
structure
homomorphism
Newman’s problem
structural realism
Opis:
Isomorphism has become a key concept for the analysis of representation in many contexts: perceptual experience, mental imagery, scientific theories, and visual artwork may all be described as standing in isomorphisms to their targets. Yet isomorphism is a technical term from mathematics—how are we to evaluate its use in fields such as philosophy, psychology, neuroscience, or physics? I suggest that we should understand appeals to isomorphism as allegorical; the upshot of this suggestion is that isomorphism claims always operate on two distinct levels of significance, with different standards of precision and evaluation. Recognizing these levels as distinct changes the landscape of debate for isomorphism-based accounts of representation: it both dissolves the well-known triviality objection to these accounts and undermines strong forms of structural realism.
Źródło:
Avant; 2019, 10, 2
2082-6710
Pojawia się w:
Avant
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Strong continuity of semigroup homomorphisms
Autorzy:
Basit, Bolis
Pryde, A.
Powiązania:
https://bibliotekanauki.pl/articles/1217352.pdf
Data publikacji:
1999
Wydawca:
Polska Akademia Nauk. Instytut Matematyczny PAN
Tematy:
representation
semigroup homomorphism
weak continuity
strong continuity
Lipschitz map
Opis:
Let J be an abelian topological semigroup and C a subset of a Banach space X. Let L(X) be the space of bounded linear operators on X and Lip(C) the space of Lipschitz functions ⨍: C → C. We exhibit a large class of semigroups J for which every weakly continuous semigroup homomorphism T: J → L(X) is necessarily strongly continuous. Similar results are obtained for weakly continuous homomorphisms T: J → Lip(C) and for strongly measurable homomorphisms T: J → L(X).
Źródło:
Studia Mathematica; 1999, 132, 1; 71-78
0039-3223
Pojawia się w:
Studia Mathematica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On the cardinality and weight spectra of compact spaces, II
Autorzy:
Juhász, Istvan
Shelah, Saharon
Powiązania:
https://bibliotekanauki.pl/articles/1205406.pdf
Data publikacji:
1997-04-10
Wydawca:
Polska Akademia Nauk. Instytut Matematyczny PAN
Tematy:
cardinality and weight spectrum
compact space
homomorphism of Boolean algebras
Opis:
Let B(κ,λ) be the subalgebra of P(κ) generated by $[κ]^{≤λ}$. It is shown that if B is any homomorphic image of B(κ,λ) then either $|B| < 2^λ$ or $|B| = |B|^λ$; moreover, if X is the Stone space of B then either $|X| ≤ 2^{2^λ}$ or $|X| = |B| = |B|^λ$. This implies the existence of 0-dimensional compact $T_2$ spaces whose cardinality and weight spectra omit lots of singular cardinals of "small" cofinality.
Źródło:
Fundamenta Mathematicae; 1998, 155, 1; 91-94
0016-2736
Pojawia się w:
Fundamenta Mathematicae
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
More on linear and metric tree maps
Autorzy:
Kozerenko, Sergiy
Powiązania:
https://bibliotekanauki.pl/articles/1397335.pdf
Data publikacji:
2021
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
Markov graph
metric map
non-expanding map
linear map
graph homomorphism
Opis:
We consider linear and metric self-maps on vertex sets of finite combinatorial trees. Linear maps are maps which preserve intervals between pairs of vertices whereas metric maps are maps which do not increase distances between pairs of vertices. We obtain criteria for a given linear or a metric map to be a positive (negative) under some orientation of the edges in a tree, we characterize trees which admit maps with Markov graphs being paths and prove that the converse of any partial functional digraph is isomorphic to a Markov graph for some suitable map on a tree.
Źródło:
Opuscula Mathematica; 2021, 41, 1; 55-70
1232-9274
2300-6919
Pojawia się w:
Opuscula Mathematica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A note on semidirect sum of Lie algebras
Autorzy:
Ostrowski, Tadeusz
Powiązania:
https://bibliotekanauki.pl/articles/729075.pdf
Data publikacji:
2013
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
Lie algebra
subalgebra
ideal
center
semidirect sum
homomorphism
derivation
Killing form
Opis:
In the paper there are investigated some properties of Lie algebras, the construction which has a wide range of applications like computer sciences (especially to computer visions), geometry or physics, for example. We concentrate on the semidirect sum of algebras and there are extended some theoretic designs as conditions to be a center, a homomorphism or a derivative. The Killing form of the semidirect sum where the second component is an ideal of the first one is considered as well.
Źródło:
Discussiones Mathematicae - General Algebra and Applications; 2013, 33, 2; 233-247
1509-9415
Pojawia się w:
Discussiones Mathematicae - General Algebra and Applications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
IF-filters of pseudo-BL-algebras
Autorzy:
Wojciechowska-Rysiawa, Magdalena
Powiązania:
https://bibliotekanauki.pl/articles/728904.pdf
Data publikacji:
2015
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
pseudo-BL-algebra
filter
IF-filter
prime IF-filters
pseudo-BL-chain
homomorphism
direct product
Opis:
Characterizations of IF-filters of a pseudo-BL-algebra are established. Some related properties are investigated. The notation of prime IF- filters and a characterization of a pseudo-BL-chain are given. Homomorphisms of IF-filters and direct product of IF-filters are studied.
Źródło:
Discussiones Mathematicae - General Algebra and Applications; 2015, 35, 2; 177-193
1509-9415
Pojawia się w:
Discussiones Mathematicae - General Algebra and Applications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
L(2, 1)-Labelings of Some Families of Oriented Planar Graphs
Autorzy:
Sen, Sagnik
Powiązania:
https://bibliotekanauki.pl/articles/30147217.pdf
Data publikacji:
2014-02-01
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
homomorphism
planar graph
girth
partial k-tree
outerplanar graph
cactus
2-dipath L(2, 1)-labeling
oriented L(2, 1)-labeling
Opis:
In this paper we determine, or give lower and upper bounds on, the 2-dipath and oriented L(2, 1)-span of the family of planar graphs, planar graphs with girth 5, 11, 16, partial k-trees, outerplanar graphs and cacti.
Źródło:
Discussiones Mathematicae Graph Theory; 2014, 34, 1; 31-48
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł

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