共查询到20条相似文献,搜索用时 46 毫秒
1.
Many authors have been concerned with embedding ∏-like continua in Rn where ∏ is some collection of polyhedra or manifolds. A similar concern has been embedding ∏-like continua in Rn up to shape. In this paper we prove two main theorems. Theorem: If n ? 2 and X is Tn-like, then X embeds in R2n. This result was conjectured by McCord for the case H1(X) finitely generated and proved by McCord for the case that H1(X) = 0 using a theorem of Isbell. The second theorem is a shape embedding theorem. Theorem: If X is Tn-like, then X embeds in Rn+2 up to shape. This theorem is proved by showing that an n-dimensional compact connected abelian topological group embeds in Rn+2. Any Tn-like continuum is shape equivalent to a k-dimensional compact connected abelian topological group for some 0 ? k ? n. 相似文献
2.
Alec Norton 《Journal of Geometric Analysis》1994,4(3):403-424
The classical Morse-Sard Theorem says that the set of critical values off:R n+k →R n has Lebesgue measure zero iff ∈C k+1. We show theC k+1 smoothness requirement can be weakened toC k+Zygmund. This is corollary to the following theorem: For integersn >m >r > 0, lets = (n ?r)/(m ?r); iff:R n →R m belongs to the Lipschitz class Λ s andE is a set of rankr forf, thenf(E) has measure zero. 相似文献
3.
In this paper we give Lp-bound edness for the operator Tu defined bywhere P(x,y) is a real nontrivial polynomial on Rn×Rn,Ωis homogeneous of degree zero,Ω∈Lq(Sn-1),q>1/(1-μ) and b(r)∈BV(R+),The result can be regarded as an improvement of F.Ricci and E.M.Stein's result for fractional oscillatory integral operator with smoothness kernel. 相似文献
4.
Bent Fuglede 《Journal of Functional Analysis》1982,49(1):57-72
It is shown how the cone (U) of superharmonic functions ?0 on an open set U in n, n ? 3, can be recovered from the cone of superharmonic functions ?0 on the whole of n by a process involving the operator of localization associated with U. Actually we treat the more general case where U is open in the Cartan-Brelot fine topology on n. As an application we obtain a new proof of a theorem of J. Bliedtner and W. Hansen on uniform approximation by continuous subharmonic functions in open sets containing a given compact set K in n. 相似文献
5.
Let m ≥ 0, n ≥ 0 be fixed integers with m + n ≠ 0 and let R be a prime ring with char(R) = 0 or m + n + 1 ≤ char(R) ≠ 2. Suppose that there exists an additive mapping T : R → R satisfying the relation 2T(x m+n+1) = x m T(x) x n + x n T(x)x m for all ${x\in R}$ . In this case T is a two-sided centralizer. 相似文献
6.
Penny Smith 《Journal of Mathematical Analysis and Applications》2002,276(2):628-641
We continue part I of this paper. Here in part II, comparison principles are proved for non-smooth sub and super solutions (with non-smooth Cauchy data) of semilinear hyperbolic PDE in compact regular domains of R+×R+ when n?3. 相似文献
7.
M. Zakaryan 《Journal of Contemporary Mathematical Analysis (Armenian Academy of Sciences)》2013,48(2):69-77
In this paper we generalize a theorem of Hardy and Littlewood concerning the growth of conjugate harmonic functions. Moreover, we obtain an estimate for Riesz systems in the upper half-space R + n+1 of R n+1. 相似文献
8.
M. Ferreira 《Advances in Applied Clifford Algebras》2009,19(2):303-323
In this paper we consider a M?bius gyrogroup on a real Hilbert space (of finite or infinite dimension) and we obtain its factorization
by gyrosubgroups and subgroups. It is shown that there is a duality relation between the quotient spaces and the orbits obtained.
As an example we will present the factorization of the M?bius gyrogroup of the unit ball in
\mathbbRn{\mathbb{R}}^{n} linked to the proper Lorentz group Spin+(1, n). 相似文献
9.
《Journal of the Egyptian Mathematical Society》2014,22(1):11-13
Let n ⩾ 1 be a fixed integer and let R be an (n + 1)!-torsion free 1-ring with identity element e. If F, d:R → R are two additive mappings satisfying F(xn+1) = F(x)(x1)n + xd(x)(x1)n−1 + x2d(x)(x1)n−2+ ⋯ +xnd(x) for all x ∈ R, then d is a Jordan 1-derivation and F is a generalized Jordan 1-derivation on R. 相似文献
10.
Penny Smith 《Journal of Mathematical Analysis and Applications》2003,283(2):557-569
We continue Part I of this paper. Here, in Part III, comparison principles are proved for nonsmooth sub and super solutions (with nonsmooth Cauchy data) of semilinear hyperbolic PDE in compact regular domains of R+×R+ when n?3, and existence of a nonsmooth solution to the nonsmooth Cauchy problem is proved by a Perron-like method. 相似文献
11.
V. G. Maz'ya 《Journal of Mathematical Sciences》1983,23(1):1997-2003
It is proved that for all fractionall the integral \(\int\limits_0^\infty {(p,\ell ) - cap(M_t )} dt^p\) is majorized by the P-th power norm of the functionu in the space ? p l (Rn) (here Mt={x∶¦u(x)¦?t} and (p,l)-cap(e) is the (p,l)-capacity of the compactum e?Rn). Similar results are obtained for the spaces W p l (Rn) and the spaces of M. Riesz and Bessel potentials. One considers consequences regarding imbedding theorems of “fractional” spaces in ?q(dμ), whereμ is a nonnegative measure in Rn. One considers specially the case p=1. 相似文献
12.
An n-dimensional cross comprises 2n+1 unit cubes: the center cube and reflections in all its faces. It is well known that there is a tiling of R n by crosses for all n. AlBdaiwi and the first author proved that if 2n+1 is not a prime then there are $2^{\aleph_{0}}$ non-congruent regular (= face-to-face) tilings of R n by crosses, while there is a unique tiling of R n by crosses for n=2,3. They conjectured that this is always the case if 2n+1 is a prime. To support the conjecture we prove in this paper that also for R 5 there is a unique regular, and no non-regular, tiling by crosses. So there is a unique tiling of R 3 by crosses, there are $2^{\aleph_{0}}$ tilings of R 4, but for R 5 there is again only one tiling by crosses. We guess that this result goes against our intuition that suggests ‘the higher the dimension of the space, the more freedom we get’. 相似文献
13.
Beverly Brechner 《Topology and its Applications》1980,11(3):231-242
A homeomorphism of Rn onto itself is called positively regular (or EC+) iff its family of non-negative iterates is pointwise equicontinuous. For EC+ homeomorphism of Rn such that some point of Rn has bounded positive semi-orbit, the nucleus M is defined, and the following theorems are proved.Theorem 1. If such a homeomorphism h:Rn→Rn has compact nucleus M, then M is a fully invariant compact AR. Further, for n≠4,5,h:Rn/M→Rn/M is conjugate to a contraction on Rn.Theorem 2. In Rn,n≠4,5,M compact iff there existsa disk D such that h(D)?IntD.Theorem 3. In R2, either M is a disk and h|M is a rotation, or h|M is periodic. The relationship between M and the irregular set of ? is also studied. 相似文献
14.
The main result of this paper is that if X is a Peano continuum such that its nth cone Cn(X) embeds into Rn+2 then X embeds into S2. This solves a problem proposed by W. Rosicki. 相似文献
15.
In this paper we describe a function F n : R + → R + such that for any hyperbolic n-manifold M with totally geodesic boundary ${\partial M \neq \emptyset}In this paper we describe a function F
n
: R
+ → R
+ such that for any hyperbolic n-manifold M with totally geodesic boundary ?M 1 ?{\partial M \neq \emptyset} , the volume of M is equal to the sum of the values of F
n
on the orthospectrum of M. We derive an integral formula for F
n
in terms of elementary functions. We use this to give a lower bound for the volume of a hyperbolic n-manifold with totally
geodesic boundary in terms of the area of the boundary. 相似文献
16.
N. A. Shirokov 《Journal of Mathematical Sciences》1987,37(5):1306-1322
Let Γ be a closed, Jordan, rectifiable curve, whose are length is commensurable with its subtending chord, leta ε int Γ, and let Rn(a) be the set of rational functions of degree ≤n, having a pole perhaps only at the pointa. Let Λα(Γ), 0 < α < 1, be the Hölder class on Γ. One constructs a system of weights γn(z) > 0 on Γ such that f∈Λα(Γ) if and only if for any nonnegative integer n there exists a function Rn, Rn ε Rn(a) such that ¦f(z) ? Rn(z)¦ ≤ cf·γn(z), z ε Γ. It is proved that the weights γn cannot be expressed simply in terms of ρ 1 + /n(z) and ρ 1 - /n(z), the distances to the level lines of the moduli of the conformal mappings of ext Γ and int Γ on \(\mathbb{C}\backslash \mathbb{D}\) . 相似文献
17.
For a given nondegenerate hypersurfaceM n in affine space ? n+1 there exist an affine connection ?, called the induced connection, and a nondegenerate metrich, called the affine metric, which are uniquely determined. The cubic formC=?h is totally symmetric and satisfies the so-called apolarity condition relative toh. A natural question is, conversely, given an affine connection ? and a nondegenerate metrich on a differentiable manifoldM n such that ?h is totally symmetric and satisfies the apolarity condition relative toh, canM n be locally immersed in ? n+1 in such a way that (?,h) is realized as the induced structure? In 1918J. Radon gave a necessary and sufficient condition (somewhat complicated) for the problem in the casen=2. The purpose of the present paper is to give a necessary and sufficient condition for the problem in casesn=2 andn≥3 in terms of the curvature tensorR of the connection ?. We also provide another formulation valid for all dimensionsn: A necessary and sufficient condition for the realizability of (?,h) is that the conjugate connection of ? relative toh is projectively flat. 相似文献
18.
Let ? be a family of 2 n+1 subsets of a 2n-element set. Then the number of disjoint pairs in ? is bounded by (1+o(1))22n . This proves an old conjecture of Erdös. Let ? be a family of 21/(k+1)+δ)n subsets of ann-element set. Then the number of containments in ? is bounded by (1-1/k+o(1))( 2 |?| ). This verifies a conjecture of Daykin and Erdös. A similar Erdös-Stone type result is proved for the maximum number of disjoint pairs in a family of subsets. 相似文献
19.
George Hutchinson 《Algebra Universalis》1977,7(1):47-84
LetR be a nontrivial ring with 1 and δ a cardinal. Let,L(R, δ) denote the lattice of submodules of a free unitaryR-module on δ generators. Let ? be the variety of modular lattices. A lattice isR-representable if embeddable in the lattice of submodules of someR-module; ?(R) denotes the quasivariety of allR-representable lattices. Let ω denote aleph-null, and let a (m, n) presentation havem generators andn relations,m, n≤ω. THEOREM. There exists a (5, 1) modular lattice presentation having a recursively unsolvable word problem for any quasivarietyV,V ? ?, such thatL(R, ω) is inV. THEOREM. IfL is a denumerable sublattice ofL(R, δ), then it is embeddable in some sublatticeK ofL(R,δ*) having five generators, where δ*=δ for infinite δ and δ*=4δ(m+1) if δ is finite andL has a set ofm generators. THEOREM. The free ?(R)-lattice on ω generators is embeddable in the free ?(R)-lattice on five generators. THEOREM. IfL has an (m, n), ?(R)-presentation for denumerablem and finiten, thenL is embeddable in someK having a (5, 1) ?(R)-presentation. 相似文献
20.
LetR n/m(z∶γ)=P n(z∶γ)/(1?γz) m be a rational approximation to exp (z),z ∈C, of ordern for all real positiveγ. In this paper we show there exists exactly one value ofγ in each of min(n+1,m) interpolation intervals such that the uniform error overR ? is at a local minimum. 相似文献