共查询到20条相似文献,搜索用时 281 毫秒
1.
Yoshiaki Fukuma 《Journal of Pure and Applied Algebra》2011,215(2):168-184
Let X be a smooth complex projective variety of dimension 3 and let L be an ample line bundle on X. In this paper, we provide a lower bound for h0(m(KX+L)) under the assumption that κ(KX+L)≥0. In particular, we get the following: (1) if 0≤κ(KX+L)≤2, then h0(KX+L)>0 holds. (2) If κ(KX+L)=3, then h0(2(KX+L))≥3 holds. Moreover we get a classification of (X,L) with κ(KX+L)=3 and h0(2(KX+L))=3 or 4. 相似文献
2.
Yoshiaki Fukuma 《Journal of Pure and Applied Algebra》2007,211(3):609-621
Let (X,L) be a polarized manifold of dimension n defined over the field of complex numbers. In this paper, we treat the case where n=3 and 4. First we study the case of n=3 and we give an explicit lower bound for h0(KX+L) if κ(X)≥0. Moreover, we show the following: if κ(KX+L)≥0, then h0(KX+L)>0 unless κ(X)=−∞ and h1(OX)=0. This gives us a partial answer of Effective Non-vanishing Conjecture for polarized 3-folds. Next for n=4 we investigate the dimension of H0(KX+mL) for m≥2. If n=4 and κ(X)≥0, then a lower bound for h0(KX+mL) is obtained. We also consider a conjecture of Beltrametti-Sommese for 4-folds and we can prove that this conjecture is true unless κ(X)=−∞ and h1(OX)=0. Furthermore we prove the following: if (X,L) is a polarized 4-fold with κ(X)≥0 and h1(OX)>0, then h0(KX+L)>0. 相似文献
3.
《Comptes Rendus de l'Academie des Sciences Series IIA Earth and Planetary Science》2001,332(2):105-108
Let H=(a,b)F be a division quaternion algebra over a field F of characteristic not 2. Denote by τ the canonical involution on H and by K a splitting field of H. If h is a skew-hermitian form over (H,τ) then, by extension of scalars to K and by Morita equivalence, we obtain a quadratic form hK over K. This gives a map of Witt groups ρ:W−1(H,τ)→W(K) induced by ρ(h)=hK. When K is a generic splitting field of H we prove in this note that the map ρ is injective. 相似文献
4.
Makoto Ishida 《Journal of Number Theory》1974,6(2):99-104
Let K be an algebraic number field, of degree n, with a completely ramifying prime p, and let t be a common divisor of n and . Then it is proved that if K does not contain the unique subfield, of degree t, of the p-th cyclotomic number field, then we have (hK, n) > 1, where hK is the class number of K. As applications, we give several results on hK of such algebraic number fields K. 相似文献
5.
Paul A Catlin 《Journal of Combinatorial Theory, Series B》1979,27(1):42-48
Let h denote the maximum degree of a connected graph H, and let χ(H) denote its chromatic, number. Brooks' Theorem asserts that if h ≥ 3, then χ(H) ≤ h, unless H is the complete graph Kh+1. We show that when H is not Kh+1, there is an h-coloring of H in which a maximum independent set is monochromatic. We characterize those graphs H having an h-coloring in which some color class consists of vertices of degree h in H. Again, without any loss of generality, this color class may be assumed to be maximum with respect to the condition that its vertices have degree h. 相似文献
6.
A problem in extremal quasiconformal extensions 总被引:2,自引:0,他引:2
Yi Qi 《中国科学A辑(英文版)》1998,41(11):1135-1141
A constantK
0
(m)
(h) is introduced for every quasisymmetric mappingh of the unit circle and every integerm≥4 which contains the constantK
0(h) (indicated by the change in module of the quadrilaterals with vertices on the circle) as a special case. A necessary and
sufficient condition is established forK
0
(m)
(h) =K
1(h). It is shown that there are infinitely many quasisymmetric mappings of the unit circle having the property thatK
0
(m)
(h)<K
1(h), wherek
1(h) is the maximal dilatation ofh. 相似文献
7.
M. A. Dubovitskaya 《Mathematical Notes》2007,81(5-6):753-756
The two-dimensional local field K = F q((u))((t)), char K = p, and its Brauer group Br(K) are considered. It is proved that, if L = K(x) is the field extension for which we have x p ? x = ut ?p =: h, then the condition that (y, f | h]K = 0 for any y ε K is equivalent to the condition f ε Im(Nm(L*)). 相似文献
8.
Frank Gerth 《Journal of Number Theory》1983,17(2):191-203
Let K be a cyclic Galois extension of the rational numbers Q of degree ?, where ? is a prime number. Let h? denote the order of the Sylow ?-subgroup of the ideal class group of K. If h? = ?s(s ≥ 0), it is known that the number of (finite) primes that ramify in K/Q is at most s + 1 (or s + 2 if K is real quadratic). This paper shows that “most” of these fields K with h? = ?s have exactly s + 1 ramified primes (or s + 2 ramified primes if K is real quadratic). Furthermore the Sylow ?-subgroup of the ideal class group is elementary abelian when h? = ?s and there are s + 1 ramified primes (or s + 2 ramified primes if K is real quadratic). 相似文献
9.
Yoshiaki Okazaki 《Journal of Mathematical Analysis and Applications》1983,93(2):397-399
Modifying the methods of Lee [J. Math. Anal. Appl.61 (1977), 1–6], we show that each μ-measurable mapping f on a normal space T into a separable linear metric space E is almost continuous, where μ is a Radon probability measure. It is shown that for every ε > 0 there exists a compact subset Kε ? T with μ(Kε) > 1 ? ε and an elementary function g(t) = ∑ni = 1hi(t) xi such that μ(t?Kε; f(t) ≠ g(t)) < ε, where xi?E and hi(t) are real bounded continuous functions with disjoint supports. 相似文献
10.
Robert Bantegnie 《Journal of Number Theory》1974,6(2):73-98
The “cylinder conjecture” is to suppose that, if K is a gauge, the critical constants of C(K) = K ×] ? 1, +1 [? Rn+1 and of its basis K ? Rn are equal. The connection with packing constants is studied. The concept of Za(ssenhaus)-packing is introduced. ⊕i=1hG + (i ? 1)a (G a lattice) is a linear h-lattice, , the maximum density for translates of K by a linear h-lattice if the translates form a Za-packing for ζ, a packing for η, and if this packing is strict for ^. For K a bounded central star body, it is possible to find H with ζ1(C(K)) ≤ 2 ζH′(K). H is precised for K a gauge and for K = Bn. It is proved by Woods' methods that ; a result of Cleaver is used. 相似文献
11.
Felix Goldberg 《Linear algebra and its applications》2009,431(12):2285-2290
Let G be a connected graph with Colin de Verdière number μ(G). We study the behaviour of μ with respect to the Cartesian product of graphs. We conjecture that if G=G1□G2, with G1,G2 connected, then μ(G)?μ(G1)+μ(G2) and prove that μ(G)?μ(G1)+h(G2)-1, where h is the Hadwiger number (i.e. the order of the largest clique minor). In addition we provide an explicit construction of a Colin de Verdière matrix with corank μ(G1)+μ(Kn) for the graph G=G1□Kn. 相似文献
12.
Recently (see De Vylder & Goovaerts (1984), this issue) so called credibility matrices have been introduced and studied in the framework of general properties of matrices, such as non-negativity, total positivity etc. In the present note we characterize a class of credibility matrices generated by the normed sequence of functions (pl, pl,…, pn) on K = [0, b] where , i=0, …, n, θ ? K, and where ?, g, h are nonnegative (eventually depending on n, n may be finite or infinite). For simplicity we suppose h to be monotonic and continuous. 相似文献
13.
Let P be the Petersen graph, and K
u(h) the complete multipartite graph with u parts of size h. A decomposition of K
u(h) into edge-disjoint copies of the Petersen graph P is called a P-decomposition of K
u(h) or a P-group divisible design of type h
u
. In this paper, we show that there exists a P-decomposition of K
u(h) if and only if h2u(u-1) o 0 mod 30{h^2u(u-1)\equiv 0 \pmod {30}} , h(u-1) o 0 mod 3{h(u-1)\equiv 0\pmod 3} , and u ≥ 3 with a definite exception (h, u) = (1, 10). 相似文献
14.
Quasi-Wilson nonconforming finite element approximation for a class of nonlinear Sobolev equa-tions is discussed on rectangular meshes. We first prove that this element has two special characters by novel approaches. One is that (▽h ( u-Ihu )1, ▽hvh) h may be estimated as order O ( h2 ) when u ∈ H3 (Ω), where Ihu denotes the bilinear interpolation of u , vh is a polynomial belongs to quasi-Wilson finite element space and ▽h denotes the piecewise defined gradient operator, h is the mesh size tending to zero. The other is that the consistency error of this element is of order O ( h2 ) /O ( h3 ) in broken H 1-norm, which is one/two order higher than its interpolation error when u ∈ H3 (Ω) /H4 (Ω). Then we derive the optimal order error estimate and su- perclose property via mean-value method and the known high accuracy result of bilinear element. Furthermore, we deduce the global superconvergence through interpolation post processing technique. At last, an extrapola- tion result of order O ( h3 ), two order higher than traditional error estimate, is obtained by constructing a new suitable extrapolation scheme. 相似文献
15.
Ong Chong Pin 《Advances in Mathematics》1975,15(3):269-311
Classical or Newtonian Mechanics is put in the setting of Riemannian Geometry as a simple mechanical system (M, K, V), where M is a manifold which represents a configuration space, K and V are the kinetic and potential energies respectively of the system. To study the geometry of a simple mechanical system, we study the curvatures of the mechanical manifold (Mh, gh) relative to a total energy value h, where Mh is an admissible configuration space and gh the Jacobi metric relative to the energy value h. We call these curvatures h-mechanical curvatures of the simple mechanical system.Results are obtained on the signs of h-mechanical curvature for a general simple mechanical system in a neighborhood of the boundary ?Mh = {xεM: V(x) = h} and in a neighborhood of a critical point of the potential function V. Also we construct functions defined globally on Mh, called curvature functions which characterize the sign of the h-mechanical curvature. Applications are made to the Kepler problem and the three-body problem. 相似文献
16.
Franz-Viktor Kuhlmann 《manuscripta mathematica》2011,136(3-4):461-474
For valued fields K of rank higher than 1, we describe how elements in the henselization K h of K can be approximated from within K; our result is a handy generalization of the well-known fact that in rank 1, all of these elements lie in the completion of K. We apply the result to show that if an element z algebraic over K can be approximated from within K in the same way as an element in K h , then K(z) is not linearly disjoint from K h over K. 相似文献
17.
C. S. Ryoo 《Journal of Applied Mathematics and Computing》2005,17(1-2):49-58
In this paper we observe the structure of the roots ofq-Bernoulli polynomials,β n (w, h|q), using numerical investigation. By numerical experiments, we demonstrate a remarkably regular structure of the real roots ofβ n (w, h|q) forq=?1/5, ?1/2. Finally, we give a table for numbers of real and complex zeros ofβ n (w, h|q). 相似文献
18.
19.
Xia-Qi Ding 《Journal of Number Theory》2006,120(2):206-212
For any integer K?2 and positive integer h, we investigate the mean value of |ζ(σ+it)|2k×logh|ζ(σ+it)| for all real number 0<k<K and all σ>1−1/K. In case K=2, h=1, this has been studied by Wang in [F.T. Wang, A mean value theorem of the Riemann zeta function, Quart. J. Math. Oxford Ser. 18 (1947) 1-3]. In this note, we give a new brief proof of Wang's theorem, and, with this method, generalize it to the general case naturally. 相似文献
20.
Yu-ping Wang 《高校应用数学学报(英文版)》2012,27(3):345-352
In this paper, we discuss the inverse problem for indefinite Sturm-Liouville operators on the finite interval [a, b]. For a fixed index n(n = 0, 1, 2, ··· ), given the weight function ω(x), we will show that the spectral sets {λ n (q, h a , h k )} +∞ k=1 and {λ-n (q, h b , h k )} +∞ k=1 for distinct h k are sufficient to determine the potential q(x) on the finite interval [a, b] and coefficients h a and h b of the boundary conditions. 相似文献