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1.
Given a set S of positive integers let ZkS(t) denote the number of k-tuples 〈m1, …, mk〉 for which mi ∈ S ? [1, t] and (m1, …, mk) = 1. Also let PkS(n) denote the probability that k integers, chosen at random from S ? [1, n], are relatively prime. It is shown that if P = {p1, …, pr} is a finite set of primes and S = {m : (m, p1pr) = 1}, then ZkS(t) = (td(S))k Πν?P(1 ? 1pk) + O(tk?1) if k ≥ 3 and Z2S(t) = (td(S))2 Πp?P(1 ? 1p2) + O(t log t) where d(S) denotes the natural density of S. From this result it follows immediately that PkS(n) → Πp?P(1 ? 1pk) = (ζ(k))?1 Πp∈P(1 ? 1pk)?1 as n → ∞. This result generalizes an earlier result of the author's where P = ? and S is then the whole set of positive integers. It is also shown that if S = {p1x1prxr : xi = 0, 1, 2,…}, then PkS(n) → 0 as n → ∞.  相似文献   

2.
In this paper we are constructing a recurrence relation of the form
i=0rωi(k)mk+i{λ} [f] = ω(k)
for integrals (called modified moments)
mk{λ}[f]df=?11 f(x)Ck(λ)(x)dx (k = 0,1,…)
in which Ck(λ) is the k-th Gegenbauer polynomial of order λ(λ > ?12), and f is a function satisfying the differential equation
i=0n Pi(x)f(i)(x) = p(x) (?1?x?1)
of order n, where p0, p1, …, pn ? 0 are polynomials, and mkλ[p] is known for every k. We give three methods of construction of such a recurrence relation. The first of them (called Method I) is optimum in a certain sense.  相似文献   

3.
Let k be a positive square free integer, N(?k)12 the ring of algebraic integers in Q(?k)12 and S the unit sphere in Cn, complex n-space. If A1,…, An are n linearly independent points of Cn then L = {u1Au + … + unAn} with ur ∈ N(?k)12 is called a k-lattice. The determinant of L is denoted by d(L). If L is a covering lattice for S, then θ(S, L) = V(S)d(L) is the covering density. L is called locally (absolutely) extreme if θ(S, L) is a local (absolute) minimum. In this paper we determine unique classes of extreme lattices for k = 1 and k = 3.  相似文献   

4.
Let S be a Dirichlet form in L2(Ω; m), where Ω is an open subset of Rn, n ? 2, and m a Radon measure on Ω; for each integer k with 1 ? k < n, let Sk be a Dirichlet form on some k-dimensional submanifold Ωk of Ω. The paper is devoted to the study of the closability of the forms E with domain C0(Ω) and defined by: (?,g)=E(?, g)+ ip=1Eki(?ki, gki) where 1 ? kp < ? < n, and where ?ki, gki denote restrictions of ?, g in C0(Ω) to Ωki. Conditions are given for E to be closable if, for each i = 1,…, p, one has ki = n ? i. Other conditions are given for E to be nonclosable if, for some i, ki < n ? i.  相似文献   

5.
Perturbations of (?Δ)m2inL2(Rk), for k ? 1 and suitable m, by distributions V for which V?(k) = 0(¦k¦α), where α = (m + 1 ? ε)2 ? k, 0 < ε ? m + 1 ? 2k, are shown to correspond to self-adjoint operators Hv, in such a way that Hv depends continuously on V, and agrees with H + V when V is sufficiently regular. These results extend joint work with Irving E. Segal [J. Functional Analysis38 (1980), 71–98], in which perturbations of (?iddx)m by distributions V with bounded Fourier transforms in L2(R1) were considered.  相似文献   

6.
If r, k are positive integers, then Tkr(n) denotes the number of k-tuples of positive integers (x1, x2, …, xk) with 1 ≤ xin and (x1, x2, …, xk)r = 1. An explicit formula for Tkr(n) is derived and it is shown that limn→∞Tkr(n)nk = 1ζ(rk).If S = {p1, p2, …, pa} is a finite set of primes, then 〈S〉 = {p1a1p2a2psas; piS and ai ≥ 0 for all i} and Tkr(S, n) denotes the number of k-tuples (x1, x3, …, xk) with 1 ≤ xin and (x1, x2, …, xk)r ∈ 〈S〉. Asymptotic formulas for Tkr(S, n) are derived and it is shown that limn→∞Tkr(S, n)nk = (p1 … pa)rkζ(rk)(p1rk ? 1) … (psrk ? 1).  相似文献   

7.
Let k and r be fixed integers such that 1 < r < k. Any positive integer n of the form n = akb, where b is r-free, is called a (k, r)-integer. In this paper we prove that if Qk,r(x) denotes the number of (k, r)-integers ≤ x, then Qk,r(x) = xζ(k)ζ(r) + Δk,r(x), where Δk,r(x) = O(x1rexp [?Blog35x (log log x)?15]), B being a positive constant depending on r and the O-estimate is uniform in k. On the assumption of the Riemann hypothesis, we improve the above order estimate of Δk,r(x) and prove that
1x1αδk,r(t)dt=0(x1kω(x))or0(x3/(4r+1)ω(x))
, according as k ≤ (4r + 1)3 or k > (4r + 1)3, where ω(x) = exp [B log x(log log x)?1].  相似文献   

8.
Let k be an odd positive integer. Davenport and Lewis have shown that the equations
a1x1k+…+anxnk=0
with integer coefficients, have a nontrivial solution in integers x1,…, xN provided that
N?[36klog6k]
Here it is shown that for any ? > 0 and k > k0(?) the equations have a nontrivial solution provided that
N?8log 2+?k log k.
  相似文献   

9.
The Turán number T(n, l, k) is the smallest possible number of edges in a k-graph on n vertices such that every l-set of vertices contains an edge. Given a k-graph H = (V(H), E(H)), we let Xs(S) equal the number of edges contained in S, for any s-set S?V(H). Turán's problem is equivalent to estimating the expectation E(Xl), given that min(Xl) ≥ 1. The following lower bound on the variance of Xs is proved:
Var(Xs)?mmn?2ks?kns?1nk1
, where m = |E(H)| and m = (kn) ? m. This implies the following: putting t(k, l) = limn→∞T(n, l, k)(kn)?1 then t(k, l) ≥ T(s, l, k)((ks) ? 1)?1, whenever sl > k ≥ 2. A connection of these results with the existence of certain t-designs is mentioned.  相似文献   

10.
Ck estimates for convex domains of finite type in Cn are known from Alexandre (C. R. Acad. Paris, Ser. I 335 (2002) 23–26). We now want to show the same result for annuli. Precisely, we show that for all convex domains D and D′ relatively compact of Cn, of finite type m and m′ such that D?D′, for all q=1,…,n?2, there exists a linear operator T1q from C0,q(D′?D) to C0,q?1(D′?D) such that for all k∈N and all (0,q)-form f, ??-closed of regularity Ck up to the boundary, T1qf is of regularity Ck+1/max(m,m′) up to the boundary and ??Tq1f=f. We fit the method of Diederich, Fisher and Fornaess to the annuli by switching z and ζ. However, the integration kernel will not have the same behavior on the frontier as in the Diederich–Fischer–Fornaess case and we have to alter the Diederich–Fornaess support function which will not be holomorphic anymore. Also, we take care of the so generated residual term in the homotopy formula and show that it is extremely regular so that solve the ?? problem for it will not be difficult. To cite this article: W. Alexandre, C. R. Acad. Sci. Paris, Ser. I 336 (2003).  相似文献   

11.
Let x?Sn, the symmetric group on n symbols. Let θ? Aut(Sn) and let the automorphim order of x with respect to θ be defined by
γθ(x)=min{k:x xθ xθ2 ? xθk?1=1}
where is the image of x under θ. Let αg? Aut(Sn) denote conjugation by the element g?Sn. Let b(g; s, k : n) ≡ ∥{x ? Sn : kγαg(x)sk}∥ where s and k are positive integers and ab denotes a divides b. Further h(s, k : n) ≡ b(1; s, k : n), where 1 denotes the identity automorphim. If g?Sn let c = f(g, s) denote the number of symbols in g which are in cycles of length not dividing the integer s, and let gs denote the product of all cycles in g whose lengths do not divide s. Then gs moves c symbols. The main results proved are: (1) recursion: if n ? c + 1 and t = n ? c ? 1 then b(g; s, 1:n)=∑is b(g; s, 1:n?1)(ti?1(i?1)! (2) reduction: b(g; s, 1 : c)h(s, 1 : i) = b(g; s, 1 : i + c); (3) distribution: let D(θ, n) ≡ {(k, b) : k?Z+ and b = b(θ; 1, k : n) ≠ 0}; then D(θ, m) = D(φ, m) ∨ m ? N = N(θ, φ) iff θ is conjugate to φ; (4) evaluation: the number of cycles in gss of any given length is smaller than the smallest prime dividing s iff b(gs; s, 1 : c) = 1. If g = (12 … pm)t and skpm then b(g;s,k:pm) {0±1(mod p).  相似文献   

12.
We improve several results published from 1950 up to 1982 on matrix functions commuting with their derivative, and establish two results of general interest. The first one gives a condition for a finite-dimensional vector subspace E(t) of a normed space not to depend on t, when t varies in a normed space. The second one asserts that if A is a matrix function, defined on a set ?, of the form A(t)= U diag(B1(t),…,Bp(t)) U-1, t ∈ ?, and if each matrix function Bk has the polynomial form
Bk(t)=i=0αkfki(t)Cki, t∈ ?, k∈{1,…,p}
then A itself has the polynomial form
A(t)=i=0d?1fi(t)Ci,t∈?
, where
d=k=1pdk
, dk being the degree of the minimal polynomial of the matrix Ck, for every k ∈ {1,…,p}.  相似文献   

13.
It is shown that the method of Chernoff developed in the preceding paper can be modified to prove the essential self-adjointness on C0(Rm) of all positive powers of the Schrödinger operator T = ? Δ + q if q real and in C(Rm) and if T ? ?a ? b ¦ x ¦2on C0(Rm).  相似文献   

14.
In two party elections with popular vote ratio pq, 12≤p=1 ?q, a theoretical model suggests replacing the so-called MacMahon cube law approximation (pq)3, for the ratio PQ of candidates elected, by the ratio ?k(p)?k(q) of the two half sums in the binomial expansion of (p+q)2k+1 for some k. This ratio is nearly (pq)3 when k = 6. The success probability gk(p)=(pa(pa+qa) for the power law (pq)a?PQ is shown to so closely approximate ?k(p)=Σ0k(r2k+1)p2k+1?rqr, if we choose a = ak=(2k+1)!4kk!k!, that 1≤?k(p)gk(p)≤1.01884086 for k≥1 if12≤p≤1. Computationally, we avoid large binomial coefficients in computing ?k(p) for k>22 by expressing 2?k(p)?1 as the sum (p?q) Σ0k(4pq)sas(2s+1), whose terms decrease by the factors (4pq)(1?12s). Setting K = 4k+3, we compute ak for the large k using a continued fraction πak2=K+12(2K+32(2K+52(2K+…))) derived from the ratio of π to the finite Wallis product approximation.  相似文献   

15.
It is shown that if A?Ωn?{Jn} satisfies
nkσk(A)?(n?k+1)2 σk?1(A)
(k=1,2,…,n)
, where σk(A) denotes the sum of all kth order subpermanent of A, then Per[λJn+(1?λ)A] is strictly decreasing in the interval 0<λ<1.  相似文献   

16.
Let Ω = {1, 0} and for each integer n ≥ 1 let Ωn = Ω × Ω × … × Ω (n-tuple) and Ωnk = {(a1, a2, …, an)|(a1, a2, … , an) ? Ωnand Σi=1nai = k} for all k = 0,1,…,n. Let {Ym}m≥1 be a sequence of i.i.d. random variables such that P(Y1 = 0) = P(Y1 = 1) = 12. For each A in Ωn, let TA be the first occurrence time of A with respect to the stochastic process {Ym}m≥1. R. Chen and A.Zame (1979, J. Multivariate Anal. 9, 150–157) prove that if n ≥ 3, then for each element A in Ωn, there is an element B in Ωn such that the probability that TB is less than TA is greater than 12. This result is sharpened as follows: (I) for n ≥ 4 and 1 ≤ kn ? 1, each element A in Ωnk, there is an element B also in Ωnk such that the probability that TB is less than TA is greater than 12; (II) for n ≥ 4 and 1 ≤ kn ? 1, each element A = (a1, a2,…,an) in Ωnk, there is an element C also in Ωnk such that the probability that TA is less than TC is greater than 12 if n ≠ 2m or n = 2m but ai = ai + 1 for some 1 ≤ in?1. These new results provide us with a better and deeper understanding of the fair coin tossing process.  相似文献   

17.
Let G be a semisimple noncompact Lie group with finite center and let K be a maximal compact subgroup. Then W. H. Barker has shown that if T is a positive definite distribution on G, then T extends to Harish-Chandra's Schwartz space C1(G). We show that the corresponding property is no longer true for the space of double cosets K\GK. If G is of real-rank 1, we construct liner functionals Tp ? (Cc(K\GK))′ for each p, 0 < p ? 2, such that Tp(f 1 f1) ? 0, ?f ? Cc(K\GK) but Tp does not extend to a continuous functional on Cp(K\GK). In particular, if p ? 1, Tv does not extend to a continuous functional on C1(K\GK). We use this to answer a question (in the negative) raised by Barker whether for a K-bi-invariant distribution T on G to be positive definite it is enough to verify that T(f 1 f1) ? 0, ?f ? Cc(K\GK). The main tool used is a theorem of Trombi-Varadarajan.  相似文献   

18.
For a(1) ? a(2) ? ··· ? a(n) ? 0, b(1) ? b(2) ? ··· ? b(n) ? 0, the ordered values of ai, bi, i = 1, 2,…, n, m fixed, m ? n, and p ? 1 it is shown that
1naibi ? 1map(i)1p1m?k?1 bq(i)+bq[m?k](k+1)qp1q
where 1p + 1q = 1, b[j] = b(j) + b(j + 1) + ··· + b(n), and k is the integer such that b(m ? k ? 1) ? b[m ? k](k + 1) and b(m ? k) < b[m ? k + 1]k. The inequality is shown to be sharp. When p < 1 and a(i)'s are in increasing order then the inequality is reversed.  相似文献   

19.
20.
Author index     
A matrix T=(tik) is introduced, the coefficients of which are defined by kik:= (ik(ik)!)Σx?Snai(x)k, i, k?N={1, 2, 3,…,}, where ai(x) denotes the s the number of i cycles in the element x of the symmetric group Sn. It is shown that these numbers are natural numbers, that they are easy to evaluate, and that they serve very well in order to formulate an infinite number of characterizations of multiply transitive subgroups of symmetric groups in terms of the cycle structure of their elements.  相似文献   

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