共查询到20条相似文献,搜索用时 31 毫秒
1.
Pavel Krejčí 《Applications of Mathematics》2000,45(6):439-468
This paper deals with the asymptotic behavior as t of solutions u to the forced Preisach oscillator equation
where
is a Preisach hysteresis operator, L
(0, ) is a given function and t 0 is the time variable. We establish an explicit asymptotic relation between the Preisach measure and the function (or, in a more physical terminology, a balance condition between the hysteresis dissipation and the external forcing) which guarantees that every solution remains bounded for all times. Examples show that this condition is qualitatively optimal. Moreover, if the Preisach measure does not identically vanish in any neighbourhood of the origin in the Preisach half-plane and
, then every bounded solution also asymptotically vanishes as t . 相似文献
2.
Raúl Figueroa 《Geometriae Dedicata》1994,50(2):205-216
Let be a non-Desarguesian semifield plane of orderp
n, p a prime number 5 andn3, and let
denote the group induced by the autotopism groupG of on the line at infinity. We prove that is a generalized twisted field plane if, and only if,
has an element of order (p
k–1)((p
n–1)/(p
m–1)), for some integersk andm, wherek | m, m | n, andm.This work was supported in part by NSF grants RII-9014056, component IV of the EPSCoR of Puerto Rico grant and ARO grant for Cornell MSI 相似文献
3.
D. M. Smirnov 《Algebra and Logic》2004,43(4):249-257
For integers 1 m < n, a Cantor variety with m basic n-ary operations i and n basic m-ary operations k is a variety of algebras defined by identities k(1(
), ... , m(
)) =
k and i(1(
), ... ,n(
)) = y
i, where
= (x
1., ... , x
n) and
= (y
1, ... , y
m). We prove that interpretability types of Cantor varieties form a distributive lattice, , which is dual to the direct product 1 × 2 of a lattice, 1, of positive integers respecting the natural linear ordering and a lattice, 2, of positive integers with divisibility. The lattice is an upper subsemilattice of the lattice
of all interpretability types of varieties of algebras. 相似文献
4.
Christos A. Athanasiadis 《Geometriae Dedicata》2001,86(1-3):37-57
The cyclic zonotope
(n, d) is the zonotope in
d
generated by any n distinct vectors of the form (1, t, t
2,..., t
d–1). It is proved that the refinement poset of all proper zonotopal subdivisions of
(n, d) which are induced by the canonical projection :
(n, d)
(n, d), in the sense of Billera and Sturmfels, is homotopy equivalent to a sphere and that any zonotopal subdivision of
(n, d) is shellable. The first statement gives an affirmative answer to the generalized Baues problem in a new special case and refines a theorem of Sturmfels and Ziegler on the extension space of an alternating oriented matroid. An important ingredient in the proofs is the fact that all zonotopal subdivisions of
(n, d) are stackable in a suitable direction. It is shown that, in general, a zonotopal subdivision is stackable in a given direction if and only if a certain associated oriented matroid program is Euclidean, in the sense of Edmonds and Mandel. 相似文献
5.
To every egglike inversive plane
there is associated a family
of involutions of the point set of
such that
circles of
are the fixed point sets of the involutions in
. Korchmaros and Olanda characterized a family
of involutions on a set of size n2 + 1to be
for
an egglike inversive plane of order n by four conditions. In this
paper, we give an alternative proof where the Galois space PG(3,n) in
which
is embedded is built up directly by using concepts and
results on finite linear spaces. 相似文献
6.
Dr. habil. F. A. Behringer 《Mathematical Methods of Operations Research》1977,21(3):103-116
Summary Letf
i
:A R ben real-valued objective functions on a convex setA -K
m
,K:=R orC, n, mN. Letg: A R
n
be defined by
, where for eachxA, (i
1
(x), ..., i
n
(x)) is a permutation of (1, ...,n) such that
. In this paper we treat the problem of findingx
*A such that
, wherel-max denotes the lexicographic maximum. If the fi's are strongly quasiconcave we can reduce the problem stepwise until finally it is in the form of a scalar programming problem. Further, we consider conditions for the existence and uniqueness of a solution and discuss the relationship of the problem to the vector maximum (i.e. Pareto) and maxmin (i.e. Chebychev) problems.
Zusammenfassung f i :AR seienn reellwertige Zielfunktionen über einer konvexen MengeA-K m ,K:=R oderC, n, mN. g:AR n sei definiert durch , wobei für jedesxA (i 1 (x), ... i n (x)) eine Permutation von (1, ...,n) derart ist, daß Wir betrachten das Problem, einx *A so zu finden, daß , wobeil-max das lexikographische Maximum bedeute. Falls dief i stark quasikonkav sind, läßt sich das Problem stufenweise reduzieren, bis es schließlich die Gestalt eines skalaren Optimierungsproblems annimmt. Wir geben Existenz- und Eindeutigkeitsbedingungen an und besprechen Zusammenhänge mit dem Vektormaximumproblem (d.h. Pareto-Optimierung) und dem Maxmin-Problem (d.h. Tschebyscheff-Optimierung).相似文献
7.
吴启光 《应用数学学报(英文版)》1995,11(4):378-388
QUADRATICESTIMATORSOFQUADRATICFUNCTIONSWITHPARAMETERSINNORMALLINEARMODELS¥WUQIGUANG(吴启光)(InstituteofSystemeScience,theChinese... 相似文献
8.
Patrick Headley 《Journal of Algebraic Combinatorics》1997,6(4):331-338
Let be an irreducible crystallographic rootsystem in a Euclidean space V, with + theset of positive roots. For ,
, let
be the hyperplane
. We define a set of hyperplanes
. This hyperplane arrangement is significant inthe study of the affine Weyl groups. In this paper it is shown that thePoincaré polynomial of
is
, where n is the rank of and h is the Coxeter number of the finiteCoxeter group corresponding to . 相似文献
9.
Paolo Cubiotti 《Set-Valued Analysis》1993,1(1):81-87
In this paper, we deal with the following generalized quasi-variational inequality problem: given a closed convex subsetX
n
, a multifunction :X 2
n
and a multifunction :X 2
X
, find a point (
) X ×
n
such that
We prove an existence theorem in which, in particular, the multifunction is not supposed to be upper semicontinuous. 相似文献
10.
Andrzej Stachurski 《Mathematical Programming》1981,20(1):196-212
In this paper the so-called Broyden's bounded-class of methods is considered. It contains as a subclass Broyden's restricted-class of methods, in which the updating matrices retain symmetry and positive definiteness. These iteration methods are used for solving unconstrained minimization problems of the following form:
It is assumed that the step-size coefficient
k = 1 in each iteration and the functionalf : R
n R1 satisfies the standard assumptions, viz.f is twice continuously differentiable and the Hessian matrix is uniformly positive definite and bounded (there exist constantsm, M > 0 such that my2 y,
for ally R
n) and satisfies a Lipschitz-like condition at the optimal point
, the gradient vanishes at
Under these assumptions the local convergence of Broyden's methods is proved. Furthermore, the Q-superlinear convergence is shown. 相似文献
11.
We prove the following theorem. Let m and n be any positive integers with mn, and let
be a subset of the n-dimensional Euclidean space
n
. For each i=1, . . . , m, there is a class
of subsets M
i
j
of
Tn
. Assume that
for each i=1, . . . , m, that M
i
j
is nonempty and closed for all i, j, and that there exists a real number B(i, j) such that
and its jth component
xjB(i, j)
imply
. Then, there exists a partition
of {1, . . . , n} such that
for all i and
We prove this theorem based upon a generalization of a well-known theorem of Birkhoff and von Neumann. Moreover, we apply this theorem to the fair allocation problem of indivisible objects with money and obtain an existence theorem. 相似文献
12.
Daniel T. Wise 《Geometriae Dedicata》2002,94(1):215-223
We construct an example of a finitely generated
group G such that rank((G
)n)=2 for all n1. For each n, we construct a finitely presented
group G
n
such that rank((G
n
)n)=2. We conjecture that if G is a word-hyperbolic group then rank(G
n
) as $ n. For each m we give an example of a residually finite
group K
m
such that K
m
has exactly two relators, but K
m
has no proper subgroups of index $ m. We construct a finitely generated
group D such that there is an epimorphism DD×D. 相似文献
13.
By combinatorial means the authors show the existence of thin sub-sets of primes, useful for Goldbach decompositions. For example, there is a set
of primes with
, such that all butO(x(ln x)–A) even integersnx can be written as
. 相似文献
14.
The dimension of a graphG=(V, E) is the minimum numberd such that there exists a representation
and a thresholdt such thatxy E iff
. We prove that d(G)n–x(G) and
wheren=|V| andx(G) is the chromatic number ofG; we present upper bounds for the dimension of graphs with a large girth and we show that the complement of a forest can be represented by unit vectors inR
6. We prove that d(G)1/15n for most graphs and that there are 3-regular graphs with d(G)c logn/log logn. 相似文献
15.
Shiquan WU 《应用数学学报(英文版)》1996,12(4):377-383
Letn, s
1,s
2, ... ands
n
be positive integers. Assume
is an integer for eachi}. For
,
, and
, denotes
p
(a)={j|1jn,a
j
p},
, and
.
is called anI
t
p
-intersecting family if, for any a,b
,a
i
b
i
=min(a
i
,b
i
)p for at leastt i's.
is called a greedyI
t
P
-intersecting family if
is anI
t
p
-intersecting family andW
p
(A)W
p
(B+A
c
) for anyAS
p
(
) and any
with |B|=t–1.In this paper, we obtain a sharp upper bound of |
| for greedyI
t
p
-intersecting families in
for the case 2ps
i
(1in) ands
1>s
2>...>s
n
.This project is partially supported by the National Natural Science Foundation of China (No.19401008) and by Postdoctoral Science Foundation of China. 相似文献
16.
A. Yu. Kolesov N. Kh. Rozov V. A. Sadovnichii 《Journal of Mathematical Sciences》2003,114(4):1491-1509
On the interval 0 x the parabolic system
is considered, where u
n
, n 2; > 0 is a parameter; D is a Hurwitz matrix; the vector-function F(u) C
(
n
;
n
) is such that the system u = 3DF(u) has an orbitally stable cycle u
0(t), u0(t) 0. It is shown that under some conditions and for 0 in the vicinity of a homogeneous cycle u = u
0(t) we can observe an infinite sequence of bifurcations of birth and death of time-periodic dissipative structures. These structures depend nontrivially on x. It is also shown that the quantity of coexisting stable periodic dissipative structures can grow indefinitely. 相似文献
17.
Zusammenfassung Es wird die Fortpflanzung elastisch-plastischer Spannungswellen in einem unendlichen Medium betrachtet, welches einer idealen Spannungs-Verformungs-Kurve folgt, Trescas Fliesskriterium unterworfen ist und einen sphärischen Hohlraum enthält, wobei an der Fläche des Hohlraumes ein Stoss
angenommen wird. Ein rechnerisches Verfahren, basiert auf endliche Differenzen, wird entwickelt and ein Beispiel gegeben.
Notation radial stress - tangential stress - K yield stress - rr non-dimensional radial stress ( /K) - non-dimensional tangential stress ( /K) - , Lame's constants - K b Bulk constant (=(3+2)/3) - v Poisson's constant - Material density - C Elastic wave velocity (=((+2)/)1/2) - C p Plastic wave velocity (=(K b /)1/2) - distance from center of cavity - r 0 cavity radius - v non-dimensional radial co-ordinate (= /r 0) - time - t non-dimensional time (=C /r 0) - radial displacement - u non-dimensional radial displacement (=/r 0) - particle velocity - v non-dimensional particle velocity (= /C) - pressure - P(t) non-dimensional pressure (= /K) 相似文献
Notation radial stress - tangential stress - K yield stress - rr non-dimensional radial stress ( /K) - non-dimensional tangential stress ( /K) - , Lame's constants - K b Bulk constant (=(3+2)/3) - v Poisson's constant - Material density - C Elastic wave velocity (=((+2)/)1/2) - C p Plastic wave velocity (=(K b /)1/2) - distance from center of cavity - r 0 cavity radius - v non-dimensional radial co-ordinate (= /r 0) - time - t non-dimensional time (=C /r 0) - radial displacement - u non-dimensional radial displacement (=/r 0) - particle velocity - v non-dimensional particle velocity (= /C) - pressure - P(t) non-dimensional pressure (= /K) 相似文献
18.
Elena Prestini 《Monatshefte für Mathematik》1988,105(3):207-216
LetfL
p(
n
),n2, be a radial function and letS
Rf be the spherical partial sums operator. We prove that if
thenS
Rf(x)f(x) a.e. asR. The result is false for
and
\frac{{2n}}{{n + 1}}$$
" align="middle" border="0">
.Partially supported by M.P.I. 相似文献
19.
A renormalization group transformation R
1 has a single stable point
in the space of the analytic circle homeomorphisms with a single cubic critical point and with the rotation number
(the golden mean). Let a homeomorphism T be the C
1-conjugate of
. We let
denote the sequence of distribution functions of the time of the kth entrance to the nth renormalization interval for the homeomorphism T. We prove that for any
, the sequence
has a finite limiting distribution function
, which is continuous in
, and singular on the interval [0,1]. We also study the sequence
for k>1. 相似文献
20.
One investigates the scattering theory for the positive self-adjoint operatorH=–· acting in
with = × and a bounded open set in
n–1,n2. The real-valued function belongs toL
(), is bounded from below byc>0 and there exist real-valued functions
1 and
2 inL
() such that –
j
,j=1,2 is a short range perturbation of
j
when (–1)
j
x
n
+. One assumes
j
=
(j)
1R,j=1,2, with
(j)
L
bounded from below byc>0. One proves the existence and completeness of the generalized wave operators
j
±
=s –
j
e
–itHj
,j=1,2, withH
j
=–·
j
and
j
: equal to 1 if (–1)
j
x
n
>0 and to 0 if (–1)
j
x
n
<0. The ranges ofW
j
±
:=(
j
±
)* are characterized so that
W
1
±
=Ran and
. The scattering operator can then be defined. 相似文献