共查询到20条相似文献,搜索用时 31 毫秒
1.
Frank Ruskey 《Order》1989,6(3):227-233
A permutation
1
2...
n
is alternating if
1<
2>
3<
4.... Alternating permutations are counted by the Euler numbers. Here we show that alternating permutations can be listed so that successive permutations differ by a transposition, ifn is odd. Extensions and open problems are mentioned.Research supported by the Natural Sciences and Engineering Research Council of Canada under grant A3379. 相似文献
2.
Mark Skandera 《Journal of Algebraic Combinatorics》2004,20(2):195-211
Let
I,I be the minor of a matrix which corresponds to row set I and column set I. We give a characterization of the inequalities of the form
I,I
K,K
J,J
L,L
which hold for all totally nonnegative matrices. This generalizes a recent result of Fallat, Gekhtman, and Johnson. 相似文献
3.
B. A. Sevast'yanov 《Mathematical Notes》1968,3(4):247-251
Conditions are found which must be imposed on a function g(x) in order that M g(1+2+ + v < if M g(i) < and M g(v) < ,, 1, 2, , n, ... being non-negative and independent, being integral, and {i} being identically distributed. The result is applied to the theory of branching processes.Translated from Matematicheskie Zametki, Vol. 3, No. 4, pp. 387–394, April, 1968. 相似文献
4.
Andrea Del Centina 《Annali di Matematica Pura ed Applicata》1985,142(1):49-55
Sunto
Sia : YY un rivestimento doppio non diramato di una curva di genere quattro definita su
C
e a moduli generali. Sia il punto di 2-divisione associate a . In questa nota si studia il sistema 2 delle quardriche di contatto al modello canonico di Y, associato al dato rivestimento.e si esplicita una biezione tra l'insieme delle theta-caratteristiche dispari di Y che diffeiscono per e l'insieme dell theta caratteristiche dispari dell curve di genere tre la cui Jacobiana e isomorfa (come v.a.p.p.) alla varieta di Prym P(f Y Y) 相似文献
5.
A permutation 1 2 ...
n
is alternating if 1<2>3<4 .... We present a constant average-time algorithm for generating all alternating permutations in lexicographic order. Ranking and unranking algorithms are also derived.Research supported by the Natural Sciences and Engineering Research Council of Canada under grant A3379. 相似文献
6.
Erik Valtonen 《manuscripta mathematica》1989,63(1):45-68
LetR be a commutative ring with 1 andM anR-module. If:M
R
MR is anR-module homomorphism satisfying(mm)=(mm) and(mm)m=m(mm), the additive abelian groupRM becomes a commutative ring, if multiplication is defined by (r,m)(r,m)=(rr+(mm),rm+rm). This ring is called the semitrivial extension ofR byM and and it is denoted byR
M. This generalizes the notion of a trivial extension and leads to a more interesting variety of examples. The purpose of this paper is to studyR
M; in particular, we are interested in some homological properties ofR
M as that of being Cohen-Macaulay, Gorenstein or regular. A sample result: Let (R,m) be a local Noetherian ring,M a finitely generatedR-module and Im() m. ThenR
M is Gorenstein if and only if eitherRM is Gorenstein orR is Gorenstein,M is a maximal Cohen-Macaulay module andMM
*, where the isomorphism is given by the adjoint of. 相似文献
7.
W. Lück 《Geometric And Functional Analysis》1994,4(4):455-481
LetX be a finite connectedCW-complex. Suppose that its fundamental group is residually finite, i.e. there is a nested sequence ...
m
+ 1
m
... of in normal subgroups of finite index whose intersection is trivial. Then we show that thep-thL
2-Betti number ofX is the limit of the sequenceb
p(Xm)/[:
m
] whereb
p(Xm) is the (ordinary)p-th Betti number of the finite covering ofX associated with
m
. 相似文献
8.
S. Sivaganesan 《Annals of the Institute of Statistical Mathematics》1993,45(1):187-199
Range of the posterior probability of an interval over the -contamination class ={=(1–)0+q:qQ} is derived. Here, 0 is the elicited prior which is assumed unimodal, is the amount of uncertainty in 0, andQ is the set of all probability densitiesq for which =(1–)0+q is unimodal with the same mode as that of 0. We show that the sup (resp. inf) of the posterior probability of an interval is attained by a prior which is equal to (1–)0 except in one interval (resp. two disjoint intervals) where it is constant. 相似文献
9.
Alan S. McRae 《Geometriae Dedicata》2001,84(1-3):321-330
If denotes the curvature and the torsion of a closed, generic, and oriented polygonal space curve X in
, then we show that
X
(2 + 2) ds =
X
ds +
X
| | ds > 4 if is positive. We also show that
X
(2 + 2) ds 2n if no four consecutive vertices lie in a plane and X has linking number n with a straight line. These extend theorems of Milnor and Totaro. 相似文献
10.
Klaus Metsch 《Designs, Codes and Cryptography》1997,10(2):251-263
We show that every non-degenerate planar space with v points and planes can be embedded as a linear space into PG(3,q) for some prime power q provided that 1000( - v) v5/6; 相似文献
11.
LetG be a subgroup of the general linear group GLn(K), where charK 2. Put Kn =V. AssumeG is generated by the setS of all elements inG for which dimV( – 1) = 1, and suppose 2=1V for each inS. If {V(–1)¦S} contains a simplex, if – 1V G, and if inG is a product of dim v(–1) elements inS wheneverV(–1) is not contained in the kernel of–1, thenG is a subgroup of an orthogonal group.This research was supported in part by NSERC Canada grant A7251.To Helmut Mäurer on his 60th birthday 相似文献
12.
Bruno Zimmermann 《Monatshefte für Mathematik》1987,104(3):247-253
LetG be a group andK(G, 1) an Eilenberg—MacLane space, i.e. 1(K(G,1))G,
i
(K(G,1))=0,i1. We give a purely algebraic proof that the second homology groupH
2(G)=H
2(G,)H
2(K(G,1)) is isomorphic to the group of stable equivalence classes of continuous mapsFK(G,1) inducing surjections on fundamental groups (resp. surjections, whereF{F
g=closed orientable surface of genusg,g}. As a corollary we obtain an algebraic proof of the well-known isomorphismH
2(G)2(K(G,1)) (2-dimensional bordism group). 相似文献
13.
On the Harris Recurrence of Iterated Random Lipschitz Functions and Related Convergence Rate Results 总被引:1,自引:0,他引:1
Gerold Alsmeyer 《Journal of Theoretical Probability》2003,16(1):217-247
A result by Elton(6) states that an iterated function system
of i.i.d. random Lipschitz maps F
1,F
2,... on a locally compact, complete separable metric space
converges weakly to its unique stationary distribution if the pertinent Liapunov exponent is a.s. negative and
for some
. Diaconis and Freedman(5) showed the convergence rate be geometric in the Prokhorov metric if
for some p>0, where L
1 denotes the Lipschitz constant of F
1. The same and also polynomial rates have been recently obtained in Alsmeyer and Fuh(1) by different methods. In this article, necessary and sufficient conditions are given for the positive Harris recurrence of (M
n
)
n0 on some absorbing subset
. If
and the support of has nonempty interior, we further show that the same respective moment conditions ensuring the weak convergence rate results mentioned above now lead to polynomial, respectively geometric rate results for the convergence to in total variation or f-norm
f
, f(x)=1+d(x,x
0)
for some (0,p]. The results are applied to various examples that have been discussed in the literature, including the Beta walk, multivariate ARMA models and matrix recursions. 相似文献
14.
Let (x) stand for the number of primes not exceedingx. In the present work it is shown that if 23/421,yx
andx>x() then (x)–(x–y)>y/(100 logx). This implies for the difference between consecutive primes the inequalityp
n+1–p
n
p
n
23/42
. 相似文献
15.
A. G. Areshkina 《Mathematical Notes》1998,64(2):154-158
On a measurable space (T, , ) we choose an additive measure: Z (Z is a Banach space) with the following property: for alle , we have
; this measure defines an indefinite integral over the measure onL
2
(T, ,). We prove that if {
n
(t)}
n
=1/
is an orthonormal basis inL
2 and
n
(e)=e
n
(t) d, then any additive measure: Z whose Radon-Nikodým derivatived/d belongs toL
2 is uniquely expandable in a series(e)=
n
=1/
n
n(e) that converges to(e) uniformly with respect toe can be differentiated term-by-term, and satisfies
n
=1/
n
/2
<. In the caseL
2[0,2],Z=, the Fourier series of a 2-periodic absolutely continuous functionF(t) such thatF'(t) L
2[0, 2] is superuniformly convergent toF(t).Translated fromMatematicheskie Zametki, Vol. 64, No. 2, pp. 180–184, August, 1998. 相似文献
16.
Christophe Breuil 《Compositio Mathematica》1999,117(2):189-203
Let k be a perfect field of characteristic p > 0, K0 = Frac(W(k)), a uniformizer in K0 and n K 0 (n N) such that 0 = and
n+1
p
= n. We write K = nN K0 (n), H = Gal (K0/ K and G = Gal(K0/ K0). The main result of this paper is that the functor restriction of the Galois action from the category of crystalline representations of G with Hodge–Tate weights in an interval of length p - 2 to the category of p-adic representations of H is fully faithful and its essential image is stable by sub-object and quotient. The proof uses the comparison between two ways of building mod. p representations of H: one thanks to the norm field of K, the other thanks to some categories of filtered modules with divided powers previously introduced by the author. 相似文献
17.
18.
Hans Schwinn 《Analysis Mathematica》1981,7(3):209-216
, (2) (1), (E, q) (0<q<1), ,
, , m
i
=i
2 (. . . [], X. [4]). , (1) (E, q) (0<q<1) (E, q), . .
相似文献
19.
Joseph L. Gerver 《Geometriae Dedicata》1984,16(1):93-106
Every polygon can be dissected into acute triangles. In this paper we prove that every polygon, such that the interior angles are at least /5, can be dissected into triangles with interior angles all less than or equal to 2/5. We find necessary conditions on the interior angles of the polygon in order to obtain a dissection into triangles with interior angles all (where /3<<2/5). The conjecture can be stated that these conditions are also sufficient. 相似文献
20.
Cheng -Tan Hsiao 《Probability Theory and Related Fields》1982,59(1):39-53
Summary LetU(x), x
d-|0}, be a nonnegative even function such that x
0U(x)1. In this paper, we consider an infinite system of stochastic process
t
(x); x
d with the following mechanism: at each sitex, after mean 1 exponential waiting time,
t(x) is replaced by a Gaussian random variable with mean
yx
t
(y) U(y-x) and variance 1. It is understood here that all the interactions are independent of one another. The behavior of this system will be investigated and some ergodic theorems will be derived. The results strongly depend whether
x
0
U(x)<1 or =1. 相似文献