共查询到20条相似文献，搜索用时 31 毫秒
1.
Davide Carlo Demaria 《Milan Journal of Mathematics》1976,46(1):139-161
Given a metric compact spaceS and a finite graphG we show that:
Hence it follows that in each class of regularn-dimensional homotopy ofG can always be chosen as representative an almost constant path in respect of a suitable triangulation ofn-cubeI
n. 相似文献
| a) | each regular function ofS inG is regularly homotopic to a strongly regular function; |
| b) | each regular function ofS inG is regularly homotopic to an almost constant function in respect of an appropriate partition ofS. |
2.
LetG be a finite nonsolvable group andH a proper subgroup ofG. In this paper we determine the structure ofG ifG satisfies one of the following conditions:
相似文献
| (1) | Every solvable subgroupK(K⊉H) is eitherp-decomposable or a Schmidt group,p being the smallest odd prime factor of |G|. |
| (2) | |G∶H| is divisible by an odd prime and every solvable subgroupK(K⊉H) is either 2′-closed or a Schmidt group. |
| (3) | |G∶H| is even and every solvable subgroupK(K⊉H) is either 2-closed or a Schmidt group. |
3.
In this paper, we discuss the representation-finite selfinjective artin algebras of classB
n andC
n and obtain the following main results:
For any fieldk, let Λ be a representation-finite selfinjective artin algebras of classB
n orC
n overk.
相似文献
| (a) | We give the configuration ofZB n andZC n. |
| (b) | We show that Λ is standard. |
| (c) | Under the condition ofk being a perfect field, we describe Λ by boundenk-species and show that Λ is a finite covering of the trivial extension of some tilted algebra of typeB n orC n. |
4.
A. A. Tuganbaev 《Mathematical Notes》1998,64(1):116-120
Rings over which every nonzero right module has a maximal submodule are calledright Bass rings. For a ringA module-finite over its centerC, the equivalence of the following conditions is proved:
Translated fromMatematicheskie Zametki, Vol. 64, No. 1, pp. 136–142, July, 1998.This research was partially supported by the Russian Foundation for Basic Research under grant No. 96-01-00627. 相似文献
| (1) | A is a tight Bass ring; |
| (2) | A is a left Bass ring; |
| (3) | A/J(A) is a regular ring, andJ(A) is a right and leftt-nilpotent ideal. |
5.
Let (G, τ) be a commutative Hausdorff locally solid lattice group. In this paper we prove the following:
As an application, a version of the Nikodym boundedness theorem for set functions with values in a class of locally solid
topological groups is established. 相似文献
| (1) | If (G, τ) has the A(iii)-property, then its completion is an order-complete locally solid lattice group. |
| (2) | If G is order-complete and τ has the Fatou property, then the order intervals of G are τ-complete. |
| (3) | If (G, τ) has the Fatou property, then G is order-dense in Ĝ and has the Fatou property. |
| (4) | The order-bound topology on any commutative lattice group is the finest locally solid topology on it. |
6.
Given a connected graph G, a vertex v of G is said to be a branch vertex if its degree is greater than 2. We consider two problems arising in the context of optical networks:
For these NP-hard problems, heuristics, that give good quality solutions, do not exist in the literature. In this paper we
analyze the relation between the problems, provide a single commodity flow formulation to solve the problems by means of a
solver and develop different heuristic strategies to compute feasible solutions that are compared with the exact ones. Our
extensive computational results show the algorithms to be very fast and effective. 相似文献
| (i) | Finding a spanning tree of G with the minimum number of branch vertices and |
| (ii) | Finding a spanning tree of G such that the degree sum of the branch vertices is minimized. |
7.
In general, given a finite group G, a prime p and a p-subgroup R of G, the sylowizers of R in G are not conjugate. In this paper we afford some conditions to achieve the conjugation of the sylowizers of R in a p-soluble group G, among others
This research has been supported by Grants: MTM2004-06067-C02-01 and MTM 2004-08219-C02-01, MEC (Spain) and FEDER (European
Union). 相似文献
| 1. | p = 2 and the Sylow 2-subgroups of G are dihedral or quaternion. |
| 2. | The Sylow p-subgroups of G have order at most p 3. |
| 3. | p is odd, R is abelian and every element of order p in C G (R) lies in R. |
8.
Belmesnaoui Aqzzouz 《Rendiconti del Circolo Matematico di Palermo》2006,55(2):147-162
We show that if (K,L) is a semi-abelian category, there exists an abelian categoryK
x with the followings properties:
相似文献
| 1 | The categoryK is a full subcategory ofK x. |
| 2 | The free objects ofK are projectives inK x. |
| 3 | A sequence ofK-morphismes isK-exact if, and only if, it isK x-exact. |
| 4 | To each objectU ofK x we can associate a surjections:X→U whereX is an object ofK. |
9.
Nous quantifions certaines inclusions d'algèbres de Lie semi-simpleshg. Nous calculons les homologies associées aux quantifications, surC((h)), d'une part des algèbres de fonctions formelles surG/H, pourHG une inclusion de groupes de Lie semi-simples associée, et d'autre part des fonctions algébriques sur SL(2,C)/T.We quantize certain inclusions of semisimple Lie algebrashg. We compute the cyclic and Hochschild homologies for theC((h))-quantizations of
相似文献
| (1) | the ring of formal functions onG/H,G andH semisimple Lie groups associated to these inclusions, and |
| (2) | the ring of algebraic functionsSL(2,C)/T (T being the nonquantized torus of SL(2, C)). |
10.
The star unfolding of a convex polytope with respect to a pointx on its surface is obtained by cutting the surface along the shortest paths fromx to every vertex, and flattening the surface on the plane. We establish two main properties of the star unfolding:
These two properties permit conceptual simplification of several algorithms concerned with shortest paths on polytopes, and
sometimes a worst-case complexity improvement as well:
相似文献
| 1. | It does not self-overlap: it is a simple polygon. |
| 2. | The ridge tree in the unfolding, which is the locus of points with more than one shortest path fromx, is precisely the Voronoi diagram of the images ofx, restricted to the unfolding. |
| • | The construction of the ridge tree (in preparation for shortest-path queries, for instance) can be achieved by an especially simpleO(n 2) algorithm. This is no worst-case complexity improvement, but a considerable simplification nonetheless. |
| • | The exact set of all shortest-path “edge sequences” on a polytope can be found by an algorithm considerably simpler than was known previously, with a time improvement of roughly a factor ofn over the old bound ofO(n 7 logn). |
| • | The geodesic diameter of a polygon can be found inO(n 9 logn) time, an improvement of the previous bestO(n 10) algorithm. |
11.
For any two 2-regular spanning subgraphs G and H of the complete multipartite graph K, necessary and sufficient conditions are found for the existence of a 2-factorization of K in which
in the case where K has an odd number of vertices. 相似文献
| 1. | the first and second 2-factors are isomorphic to G and H respectively, and |
| 2. | each other 2-factor is a hamilton cycle |
12.
We present a new pivot-based algorithm which can be used with minor modification for the enumeration of the facets of the
convex hull of a set of points, or for the enumeration of the vertices of an arrangement or of a convex polyhedron, in arbitrary
dimension. The algorithm has the following properties:
For example, the algorithm finds thev vertices of a polyhedron inR
d defined by a nondegenerate system ofn inequalities (or, dually, thev facets of the convex hull ofn points inR
d, where each facet contains exactlyd given points) in timeO(ndv) andO(nd) space. Thev vertices in a simple arrangement ofn hyperplanes inR
d can be found inO(n
2
dv) time andO(nd) space complexity. The algorithm is based on inverting finite pivot algorithms for linear programming. 相似文献
| (a) | Virtually no additional storage is required beyond the input data. |
| (b) | The output list produced is free of duplicates. |
| (c) | The algorithm is extremely simple, requires no data structures, and handles all degenerate cases. |
| (d) | The running time is output sensitive for nondegenerate inputs. |
| (e) | The algorithm is easy to parallelize efficiently. |
13.
Ronen Peretz 《Israel Journal of Mathematics》1999,109(1):181-187
LetF(X, Y) be a two dimensional polynomial map overC. We show how to use the notion of induced resultants in order to give short and elementary proofs to the following three
theorems:
相似文献
| 1. | If the Jacobian of F is a non-zero constant, then the image of F contains all of C2 except for a finite set. |
| 2. | If F is invertible, then the inverse map is determined by the free terms of the induced resultants. |
| 3. | If F is invertible, then the degree of F equals the degree of its inverse. |
14.
We consider smooth non-degenerate surfaces in ℙ4, and prove that there is a finite number of such surfaces which are:
A complete list is given in both cases. 相似文献
| (a) | sectionally non-special, i.e.h1(O C(1))=0, where C is a general hyperplane section of S; or |
| (b) | not of general type and non-special (i.e. h1(O C(1))=0. |
15.
M. Rovinsky 《Selecta Mathematica, New Series》2009,15(2):343-376
Let G be the automorphism group of an extension of algebraically closed fields of characteristic zero of transcendence degree n, 1 ≤ n ≤ ∞. In this paper we
The study of open subgroups is motivated by the study of (the stabilizers of) smooth representations undertaken in [R1, R3].
The functor Γ is an analogue of the global sections functor on the category of sheaves on a smooth proper algebraic variety.
Another result is that ‘interesting’ semilinear representations are ‘globally generated’.
相似文献
| • | construct some maximal closed non-open subgroups Gv, and some (all, in the case of countable transcendence degree) maximal open proper subgroups of G; |
| • | describe, in the case of countable transcendence degree, the automorphism subgroups over the intermediate subfields (a question of Krull, [K2, §4, question 3b)]); |
| • | construct, in the case n = ∞, a fully faithful subfunctor ( − )v of the forgetful functor from the category of smooth representations of G to the category of smooth representations of Gv; |
| • | construct, using the functors ( − )v, a subfunctor Γ of the identity functor on , coincident (via the forgetful functor) with the functor Γ on the category of admissible semilinear representations of G constructed in [R3] in the case n = ∞ and . |
16.
In this paper, we show the equivalence of somequasi-random properties for sparse graphs, that is, graphsG with edge densityp=|E(G)|/(
2
n
)=o(1), whereo(1)→0 asn=|V(G)|→∞. Our main result (Theorem 16) is the following embedding result. For a graphJ, writeN
J(x) for the neighborhood of the vertexx inJ, and letδ(J) andΔ(J) be the minimum and the maximum degree inJ. LetH be atriangle-free graph and setd
H=max{δ(J):J⊆H}. Moreover, putD
H=min{2d
H,Δ(H)}. LetC>1 be a fixed constant and supposep=p(n)≫n
−1
D
H. We show that ifG is such that
Moreover, we discuss a setting under which an arbitrary graphH (not necessarily triangle-free) can be embedded inG. We also present an embedding result for directed graphs.
Research supported by a CNPq/NSF cooperative grant.
Partially supported by MCT/CNPq through ProNEx Programme (Proc. CNPq 664107/1997-4) and by CNPq (Proc. 300334/93-1 and 468516/2000-0).
Partially supported by NSF Grant 0071261.
Supported by NSF grant CCR-9820931. 相似文献
| (i) | deg G (x)≤C pn for allx∈V(G), | ||
| (ii) |
for all 2≤r≤D
H and for all distinct verticesx
1, ...,x
r ∈V(G), |
||
| (iii) |
for all but at mosto(n
2) pairs {x
1,x
2} ⊆V(G), |
17.
LetE be a set and letL be a family of subsets ofE. A subsets ofE is called atransversal ofL ifs intersects each member ofL in exactly one element, that is |sl|=1, for everyl inL. We denoteT(L) the set of all transversals ofL. A pairB=(L, C) of families of subsets ofE is abox onE if it satisfies the following conditions:
Boxes have been introduced by Boë [2]. Our aim in this paper is to study particular boxes, using techniques of ordered sets and graphs. 相似文献
| (i) | L=C=E, that is bothL andC coverE. |
| (ii) | T(L)=C andT(C)=L. |
18.
Marie-Claude Arnaud 《Annales Henri Poincare》2008,9(5):881-926
In this article, we prove different results concerning the regularity of the C
0-Lagrangian invariant graphs of the Tonelli flows. For example :
Submitted: July 23, 2007. Accepted: February 14, 2008. 相似文献
| • | in dimension 2 and in the autonomous generic case, we prove that such a graph is in fact C 1 on some set with (Lebesgue) full measure; |
| • | under certain dynamical additional hypothesis, we prove that these graphs are C 1. |
Résumé. Dans cet article, on démontre différents résultats concernant la régularité des graphes C 0-lagrangiens invariants par des flots de Tonelli. Par exemple :
• en dimension 2, dans le cas autonome et générique, on montre que ces graphes sont de classe C 1 sur un ensemble de mesure (de Lebesque) pleine; • sous certaines hypothèses concernant la dynamique restreinte, on montre que ces graphes sont de classe C 1.
Submitted: July 23, 2007. Accepted: February 14, 2008. 相似文献
19.
LetK be a class of spaces which are eigher a pseudo-opens-image of a metric space or ak-space having a compact-countable closedk-network. LetK′ be a class of spaces which are either a Fréchet space with a point-countablek-network or a point-G
δ
k-space having a compact-countablek-network. In this paper, we obtain some sufficient and necessary conditions that the products of finitely or countably many
spaces in the classK orK′ are ak-space. The main results are that
Project supported by the Mathematical Tianyuan Foundation of China 相似文献
| Theorem A | If X, Y∈K. Then X x Y is a k-space if and only if (X, Y) has the Tanaka's condition. |
| Theorem B | The following are equivalent: |
| (a) | BF(ω 2)is false. |
| (b) | For each X, Y ∈ K′, X x Y is a k-space if and only if (X,Y) has the Tanaka's condition. |
20.
Let G be a 2-edge-connected simple graph with girth g, independence number α(G), and if one of the following two conditions holds
then G is upper embeddable and the lower bound v − 3g + 7 is best possible. Similarly the result for 3-edge-connected simple graph with girth g and independence number α(G) is also obtained.
Huang Yuanqiu: Partially supported by National Science Foundation of China (No. 10771062) and Program for New Century Excellent
Talents in University (No. NCET-07-0276). 相似文献
| (1) | α(G) ≤ 2; | |
| (2) | α(G) ≥ 3, and for any three nonadjacent vertices v
i
(i = 1,2,3), it has
|