共查询到20条相似文献,搜索用时 0 毫秒
1.
Marta Pérez Rodríguez 《Journal of Pure and Applied Algebra》2008,212(11):2381-2388
We provide the main results of a deformation theory of smooth formal schemes as defined in [L. Alonso Tarrío, A. Jeremías López, M. Pérez Rodríguez, Infinitesimal lifting and Jacobi criterion for smoothness on formal schemes, Comm. Algebra 35 (2007) 1341-1367]. Smoothness is defined by the local existence of infinitesimal liftings. Our first result is the existence of an obstruction in a certain Ext1 group whose vanishing guarantees the existence of global liftings of morphisms. Next, given a smooth morphism f0:X0→Y0 of noetherian formal schemes and a closed immersion Y0?Y given by a square zero ideal I, we prove that the set of isomorphism classes of smooth formal schemes lifting X0 over Y is classified by and that there exists an element in which vanishes if and only if there exists a smooth formal scheme lifting X0 over Y. 相似文献
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Given a univariate complex interval polynomial F, we provide a rigorous method for deciding whether there exists a pseudozero of F in a prescribed closed complex domain D. Here a pseudozero of F is defined to be a zero of some polynomial in F. We use circular intervals and assume that the boundary C of D is a simple curve and that C is the union of a finite number of arcs, each of which is represented by a rational function. When D is not bounded, we assume further that all the polynomials in F are of the same degree. Examples of such domains are the outside of an open disk and a half-plane with boundary. Our decision
method uses the representation of C and the property that a polynomial in F is of degree 1 with respect to each coefficient regarded as a variable.
相似文献
3.
F.-V. KuhlmannS. Kuhlmann M. Marshall M. Zekavat 《Journal of Pure and Applied Algebra》2002,169(1):71-90
In the paper it is shown how an embedding of an ordered field F into a formal power series field can be extended canonically to an embedding of any simple extension F(y) of F. Properties of the extended embedding are studied in detail. Several applications are given. 相似文献
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Stef Graillat 《Mathematics in Computer Science》2007,1(2):337-352
The pseudozero set of a system P of polynomials in n variables is the subset of C
n
consisting of the union of the zeros of all polynomial systems Q that are near to P in a suitable sense. This concept arises naturally in Scientific Computing where data often have a limited accuracy. When
the polynomials of the system are polynomials with complex coefficients, the pseudozero set has already been studied. In this
paper, we focus on the case where the polynomials of the system have real coefficients and such that all the polynomials in
all the perturbed polynomial systems have real coefficients as well. We provide an explicit definition to compute this pseudozero
set. At last, we analyze different methods to visualize this set.
相似文献
6.
Zhongming Tang 《Archiv der Mathematik》2008,90(3):200-208
Let J
I be two proper ideals of a commutative Noetherian ring and M a finitely generated module. Strong relative depth is defined and characterized. It is proved that this depth is just the
maximum integer n such that can be annihilated by some power of J for all i ≤ n. It turns out that the local-global principle for the annihilation of local cohomology modules can be formulated as a natural
property of this new depth.
Received: 28 July 2006 相似文献
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This paper proves a generalization of Shafarevich's Conjecture, for fields of Laurent series in two variables over an arbitrary field. This result says that the absolute Galois group GK of such a field K is quasi-free of rank equal to the cardinality of K, i.e. every non-trivial finite split embedding problem for GK has exactly proper solutions. We also strengthen a result of Pop and Haran-Jarden on the existence of proper regular solutions to split embedding problems for curves over large fields; our strengthening concerns integral models of curves, which are two-dimensional. 相似文献
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Ruedi Flüge 《Differential Geometry and its Applications》2006,24(6):660-669
We refine recent existence and uniqueness results, for the barycenter of points at infinity of Hadamard manifolds, to measures on the sphere at infinity of symmetric spaces of non compact type and, more specifically, to measures concentrated on single orbits. The barycenter will be interpreted as the maximum likelihood estimate (MLE) of generalized Cauchy distributions on Furstenberg boundaries. As a spin-off, a new proof of the general Knight-Meyer characterization theorem will be given. 相似文献
12.
On the one hand, for a general Calabi–Yau complete intersection X, we establish a decomposition, up to rational equivalence, of the small diagonal in X×X×X, from which we deduce that any decomposable 0-cycle of degree 0 is in fact rationally equivalent to 0, up to torsion. On the other hand, we find a similar decomposition of the smallest diagonal in a higher power of a hypersurface, which provides us an analogous result on the multiplicative structure of its Chow ring. 相似文献
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The notion of a Bezout operator, previously known for some special classes of scalar entire functions and for matrix and operator polynomials, is introduced for general analytic operator functions. Our approach is based on representing the operator functions involved in realized form. Basic properties of Bezout operators are established and known Bezout operators are shown to be specific realizations of our general concept.The work of this author was supported by the United States-Israel Binational Science Foundation Grant 88-00304. 相似文献
16.
In this work we analyze some topological properties of the remainder of the semialgebraic Stone–Cěch compactification of a semialgebraic set in order to ‘distinguish’ its points from those of M. To that end we prove that the set of points of that admit a metrizable neighborhood in equals where is the largest locally compact dense subset of M and is the closure in M of the set of 1-dimensional points of M. In addition, we analyze the properties of the sets and of free maximal ideals associated with formal and semialgebraic paths. We prove that both are dense subsets of the remainder ?M and that the differences and are also dense subsets of ?M. It holds moreover that all the points of have countable systems of neighborhoods in . 相似文献
17.
Based on the Borel transformation and the Hadamard multiplication theorem on singularities on the convolution of holomorphic
functions, results on the growth of entire functions defined by convolution of an entire function of exponential type with
a function holomorphic at the origin are obtained.
Received: 29 August 2005 相似文献
18.
Kanetomo Sato 《Mathematische Zeitschrift》2007,257(4):707-743
In this paper, we define two kinds (homological and cohomological) of étale logarithmic Hodge–Witt sheaves on normal crossing
varieties over a perfect field of positive characteristic, and discuss some fundamental properties, in particular puity and
duality. 相似文献
19.
Jürgen J. Voss 《Journal of Fourier Analysis and Applications》1999,5(2-3):193-201
It is well known that for certain sequences {tn}n the usual Lp norm ·p in the Paley-Wiener space PW
p
is equivalent to the discrete norm fp,{tn}:=(
n=–
|f(tn)|p)1/p for 1 p = < and f,{tn}:=sup
n|f(tn| for p=). We estimate fp from above by Cfp,
n
and give an explicit value for C depending only on p, , and characteristic parameters of the sequence {tn}n. This includes an explicit lower frame bound in a famous theorem of Duffin and Schaeffer. 相似文献
20.
Let X° be the space of all labeled tetrahedra in P3. In [E. Babson, P.E. Gunnells, R. Scott, A smooth space of tetrahedra, Adv. Math. 165(2) (2002) 285-312] we constructed a smooth symmetric compactification of X°. In this article we show that the complement is a divisor with normal crossings, and we compute the cohomology ring . 相似文献