共查询到20条相似文献,搜索用时 0 毫秒
1.
Nicola Durante 《Journal of Geometry》2001,70(1-2):44-58
In this paper finite {s-2, s}-semiaffine linear spaces of order n are studied. It is proved that if s= 6 or then there is only a finite number of such linear spaces.
Received 28 May 1999; revised 28 December 1999. 相似文献
2.
Sven-Ake Wegner 《Annali dell'Universita di Ferrara》2014,60(2):447-463
The classical theory of Sobolev towers allows for the construction of an infinite ascending chain of extrapolation spaces and an infinite descending chain of interpolation spaces associated with a given \(C_0\) -semigroup on a Banach space. In this note we first generalize the latter to the case of a strongly continuous and exponentially equicontinuous semigroup on a complete locally convex space. As a new concept—even for \(C_0\) -semigroups on Banach spaces—we then define a universal extrapolation space as the completion of the inductive limit of the ascending chain. Under mild assumptions we show that the semigroup extends to this space and that it is generated by an automorphism of the latter. Dually, we define a universal interpolation space as the projective limit of the descending chain. We show that the restriction of the initial semigroup to this space is again a semigroup and always has an automorphism as generator. 相似文献
3.
In this paper finite, partially proper {0,1}-semiaffine, planes of order n are studied and completely characterized. Finite, partially {0}-semiaffine, planes are completely classified and finite, partially {1}-semiaffine, planes are classified for bn
2+n+1. 相似文献
4.
Dragana S. Cvetkovi?-Ili? Predrag S. Stanimirovi? Marko Miladinovi? 《Applied mathematics and computation》2011,218(5):1512-1514
We give a comment on some recent results concerning the representations of generalized {2, 3} and {2, 4}-inverses. Shorter proofs of some previous results are presented. 相似文献
5.
Given the integer polyhedronP
t
:= conv{x ∈ℤ
n
:Ax⩽b}, whereA ∈ℤ
m × n
andb ∈ℤ
m
, aChvátal-Gomory (CG)cut is a valid inequality forP
1 of the type λτAx⩽⌊λτb⌋ for some λ∈ℝ
+
m
such that λτA∈ℤ
n
. In this paper we study {0, 1/2}-CG cuts, arising for λ∈{0, 1/2}
m
. We show that the associated separation problem, {0, 1/2}-SEP, is equivalent to finding a minimum-weight member of a binary
clutter. This implies that {0, 1/2}-SEP is NP-complete in the general case, but polynomially solvable whenA is related to the edge-path incidence matrix of a tree. We show that {0, 1/2}-SEP can be solved in polynomial time for a
convenient relaxation of the systemAx<-b. This leads to an efficient separation algorithm for a subclass of {0, 1/2}-CG cuts, which often contains wide families of
strong inequalities forP
1. Applications to the clique partitioning, asymmetric traveling salesman, plant location, acyclic subgraph and linear ordering
polytopes are briefly discussed. 相似文献
6.
We consider a variant of the classical problem of finding the size of the largest cap in ther-dimensional projective geometry PG(r, 3) over the field IF3 with 3 elements. We study the maximum sizef(n) of a subsetS of IF
3
n
with the property that the only solution to the equationx
1+x2+x3=0 isx
1=x2=x3. Letc
n=f(n)1/n andc=sup{c
1, c2, ...}. We prove thatc>2.21, improving the previous lower bound of 2.1955 ... 相似文献
7.
8.
9.
We study the stability in the $H^1$ -seminorm of the $L_2$ -projection onto finite element spaces in the case of nonuniform but shape regular meshes in two and three dimensions and prove, in particular, stability for conforming triangular elements up to order twelve and conforming tetrahedral elements up to order seven. 相似文献
10.
V. I. Dmitriev 《Mathematical Notes》1975,17(5):433-438
Let A0, A1 be a pair of normed spaces, having the property that the difference K(x, t; A0, A1) ?K(x, s; A0, A1) regarded as a function of xε A0+ A1 is a seminorm for t>s (here K is the Oklander-Peetre functional). All the pairs A, L of normed spaces, such that, if a linear operator is bounded from A0 into L1 and from A1 into L∞, then it is bounded from A into L, are characterized in the following article. 相似文献
11.
We introduce a concept of independence entropy for symbolic dynamical systems. This notion of entropy measures the extent to which one can freely insert symbols in positions without violating the constraint defined by the shift space. We show that for a certain class of one-dimensional shift spaces X, the independence entropy coincides with the limiting, as d tends to infinity, topological entropy of the dimensional shift defined by imposing the constraints of X in each of the d cardinal directions. This is of interest because for these shift spaces independence entropy is easy to compute. Thus, while in these cases, the topological entropy of the d-dimensional shift (d≥2) is difficult to compute, the limiting topological entropy is easy to compute. In some cases, we also compute the rate of convergence of the sequence of d-dimensional entropies. This work generalizes earlier work on constrained systems with unconstrained positions. 相似文献
12.
Let (G n) be a sequence which is dense (in the sense of the Banach-Mazur distance coefficient) in the class of all finite dimensional Banach spaces. Set \(C_p = (\Sigma G_n )_{l_p } (1< p< \infty ) = (\Sigma G_n )_{c_0 } \) . It is shown that a Banach spaceX is isomorphic to a subspace ofC p (1<p≦∞) if and only ifX is isomorphic to a quotient space ofC p. 相似文献
13.
14.
15.
16.
We study some properties of generalized submaximal spaces and introduce the notion of generalized door spaces. Furthermore we extend these notions to generalized \({G_\delta}\)-submaximal spaces by replacing \({\mu}\)-open sets by \({\mu-G_\delta}\)-sets and consider some of their properties. 相似文献
17.
Luca Martinazzi 《Calculus of Variations and Partial Differential Equations》2009,36(4):493-506
Given an open bounded domain \({\Omega\subset\mathbb {R}^{2m}}\) with smooth boundary, we consider a sequence \({(u_k)_{k\in\mathbb{N}}}\) of positive smooth solutions towhere λ k → 0+. Assuming that the sequence is bounded in \({H^m_0(\Omega)}\) , we study its blow-up behavior. We show that if the sequence is not precompact, thenwhere Λ1 = (2m ? 1)!vol(S 2m ) is the total Q-curvature of S 2m .
相似文献
$\left\{\begin{array}{ll} (-\Delta)^m u_k=\lambda_k u_k e^{mu_k^2} \quad\quad\quad\quad\quad {\rm in}\,\Omega\\ u_k=\partial_\nu u_k=\cdots =\partial_\nu^{m-1} u_k=0 \quad {\rm on }\, \partial \Omega, \end{array}\right.$
$\liminf_{k\to\infty}\|u_k\|^2_{H^m_0}:=\liminf_{k\to\infty}\int\limits_\Omega u_k(-\Delta)^m u_k dx\geq \Lambda_1,$
18.
Predrag S. Stanimirovi? Dragana S. Cvetkovi?-Ili? Sladjana Miljkovi? Marko Miladinovi? 《Applied mathematics and computation》2011,217(22):9358-9367
We present the full-rank representations of {2, 4} and {2, 3}-inverses (with given rank as well as with prescribed range and null space) as particular cases of the full-rank representation of outer inverses. As a consequence, two applications of the successive matrix squaring (SMS) algorithm from [P.S. Stanimirovi?, D.S. Cvetkovi?-Ili?, Successive matrix squaring algorithm for computing outer inverses, Appl. Math. Comput. 203 (2008) 19-29] are defined using the full-rank representations of {2, 4} and {2, 3}-inverses. The first application is used to approximate {2, 4}-inverses. The second application, after appropriate modifications of the SMS iterative procedure, computes {2, 3}-inverses of a given matrix. Presented numerical examples clarify the purpose of the introduced methods. 相似文献
19.
G. L. O'Brien 《Probability Theory and Related Fields》1980,53(1):35-49
Summary Let r2 be an integer and let : {0, 1}
r
{0,1} be a function. Let T be the transformation on ={0, 1}zgiven by (T)(i)=((ri), (ri +1), ..., (ri+r–1)) for all iZ. For P in the class of strongly-mixing shiftinvariant measures on , we investigate when P is invariant with respect to T and when T
nP converges. For example if r is odd and (
0,...,
r–1)=1 iff >1/2r, the invariant measures are the Bernoulli measures with means 0, 1/2 or 1 and T
nP must converge to one of these three measures. Other choices of can give more complicated behaviour.Research supported in part by the National and Engineering Research Council of Canada. 相似文献