共查询到20条相似文献,搜索用时 31 毫秒
1.
Michael Klemm 《Journal of Combinatorial Theory, Series A》1984,36(3):364-372
Let d be the minimum distance of an (n, k) code , invariant under an abelian group acting transitively on the basis of the ambient space over a field F with char F × n. Assume that contains the repetition code, that dim( ∏ ⊥) = k ? 1 and that the supports of the minimal weight vectors of form a 2-design. Then d2 ? d + 1 ? n with equality if and only if the design is a projective plane of order d ? 1. The case d2 ? d + 1 = n can often be excluded with Hall's multiplier theorem on projective planes, a theorem which follows easily from the tools developed in this paper Moreover, if d2 ? d + 1 > n and F = GF(2) then (d ? 1)2 ? n. Examples are the generalized quadratic residue codes. 相似文献
2.
Tom M. Apostol 《Journal of Number Theory》1982,15(1):14-24
An elementary proof is given of the author's transformation formula for the Lambert series relating Gp(e2πiτ) to Gp(e2πiAτ), where p > 1 is an odd integer and is a general modular substitution. The method extends Sczech's argument for treating Dedekind's function , and uses Carlitz's formula expressing generalized Dedekind sums in terms of Eulerian functions. 相似文献
3.
Brother Joseph Heisler 《Journal of Number Theory》1974,6(1):50-51
We shall establish for all finite fields GF(pn) the following result of Chowla: given a positive integer m greater than one and the finite field GF(p), p a prime, such that xm = ?1 is solvable in GF(p), then there exists an absolute positive constant c, , such that for each set of s nonzero elements ai of GF(p), has a non-trivial zero in GF(p) if s ≥ c ln m. 相似文献
4.
J. V. Brawley 《Linear algebra and its applications》1975,10(3):199-217
Let F=GF(q) denote the finite field of order q, and let . Then f(x) defines, via substitution, a function from Fn×n, the n×n matrices over F, to itself. Any function which can be represented by a polynomialf(x)?F[x] is called a scalar polynomial function on Fn×n. After first determining the number of scalar polynomial functions on Fn×n, the authors find necessary and sufficient conditions on a polynomial in order that it defines a permutation of (i) n, the diagonalizable matrices in Fn×n, (ii)n, the matrices in Fn×n all of whose roots are in F, and (iii) the matric ring Fn×n itself. The results for (i) and (ii) are valid for an arbitrary field F. 相似文献
5.
Arnošt J.J Heidrich 《Journal of Number Theory》1977,9(4):413-419
Let p be an odd prime and n an integer relatively prime to p. In this work three criteria which give the value of the Legendre symbol () are developed. The first uses two adjacent rows of Pascal's triangle which depend only on p to express () explicitly in terms of the numerically least residues (mod p) of the numbers n, 2n, …, [ or of the numbers . The second, analogous to a theorem of Zolotareff and valid only if p ≡ 1 (mod 4), expresses () in terms of the parity of the permutation of the set {} defined by the absolute values of the numerically least residues of . The third is a result dual to Gauss' lemma which can be derived directly without Euler's criterion. The applications of the dual include a proof of Gauss' lemma free of Euler's criterion and a proof of the Quadratic Reciprocity Law. 相似文献
6.
For finite graphs F and G, let NF(G) denote the number of occurrences of F in G, i.e., the number of subgraphs of G which are isomorphic to F. If and are families of graphs, it is natural to ask then whether or not the quantities NF(G), F∈, are linearly independent when G is restricted to . For example, if = {K1, K2} (where Kn denotes the complete graph on n vertices) and is the family of all (finite) trees, then of course NK1(T) ? NK2(T) = 1 for all T∈. Slightly less trivially, if = {Sn: n = 1, 2, 3,…} (where Sn denotes the star on n edges) and again is the family of all trees, then Σn=1∞(?1)n+1NSn(T)=1 for all T∈. It is proved that such a linear dependence can never occur if is finite, no F∈ has an isolated point, and contains all trees. This result has important applications in recent work of L. Lovász and one of the authors (Graham and Lovász, to appear). 相似文献
7.
Chungming An 《Journal of Number Theory》1974,6(1):1-6
A Dirichlet series associated with a positive definite form of degree δ in n variables is defined by where ? ∈ , α ∈ n, 〈x, y〉 = x1y1 + ? + xnyn, e(a) = exp (2πia) for a ∈ , and s = σ + ti is a complex number. The author proves that: (1) DF(s, ?, α) has analytic continuation into the whole s-plane, (2) DF(s, ?, α), ? ≠ 0, is a meromorphic function with at most a simple pole at . The residue at is given explicitly. (3) ? = 0, α ? n, DF(s, 0, α) is analytic for . 相似文献
8.
Let xm ? a be irreducible over F with char and let α be a root of xm ? a. The purpose of this paper is to study the lattice of subfields of and to this end is defined to be the number of subfields of F(α) of degree k over is explicitly determined for p a prime and the following structure theorem for the lattice of subfields is proved. Let N be the maximal normal subfield of F(α) over F and set n = |N : F|, then . The irreducible binomials xs ? b, xs ? c are said to be equivalent if there exist roots βs = b, γs = a such that F(β) = F(γ). All the mutually inequivalent binomials which have roots in F(α) are determined. Finally these results are applied to the study of normal binomials and those irreducible binomials x2e ? a which are normal over F (char F ≠ 2) together with their Galois groups are characterized. 相似文献
9.
William T. Stout 《Journal of Number Theory》1973,5(2):116-122
Let K and K′ be number fields with L = K · K′ and F = KφK′. Suppose that and are normal extensions of degree n. Let be a prime ideal in L and suppose that is totally ramified in and in . Let π be a prime element for K = φ K, and let f(x) ∈ F[x] be the minimum polynomial for π over F. Suppose that K · L = (≠)e. Then, , where and m is the largest integer such that (K′)nm/e φ f(K′) ≠ {φ}.If we assume in addition to the above hypotheses that [K : F] = [K′: F] = pn, a prime power, and that divides p and is totally ramified in , then , with t = t( : L/F). 相似文献
10.
Let F be a Sperner family of subsets of {1,…,m}. Bollobás showed that if , and if the parameters of F are p0,…,pm then Here we generalize this result and prove some analogues of it. A corollary of Bollobás' result is that . Purdy proved that if then , which implies Bollobás' corollary. We also show that Purdy's result may be deduced from Bollobás' by a short argument. Finally, we give a canonical form for Sperner families which are also pairwise intersecting. 相似文献
11.
Lee K. Jones 《Discrete Mathematics》1976,15(1):107-108
Nous donnons une généralisation et une démonstration très courte d'un théorème de Kleitman qui dit: Pour toute paire d'idéaux , (β) d'éléments dans le produit cartésien de k ensembles totalement ordonnés P = [1, 2, … n1] ? … ? [1, 2, … nk], nous avons (). ( ou en langage probabiliste . 相似文献
12.
B. Roth 《Journal of Functional Analysis》1975,18(4):329-337
Let [(Ω)]p be the Cartesian product of the space of real-valued infinitely differentiable functions on a connected open set Ω in n with itself p-times. The finitely generated submodules of [(Ω)]p are of the form im(F) where F: [(Ω)]q → [(Ω)]p is a p × q matrix of infinitely differentiable functions on Ω. Let . The main results of the present paper are that for Ω ? n, if the finitely generated submodule im(F) is closed in [(Ω)]p, then for every x?ω with rank(F(x)) < r there exists an r × r sub-matrix A of F such that x is a zero of finite order of det(A), and for Ω ? 1 the converse also holds. 相似文献
13.
J.W Layman 《Journal of Combinatorial Theory, Series A》1985,40(1):161-168
For any prime p, the sequence of Bell exponential numbers Bn is shown to have p ? 1 consecutive values congruent to zero (mod p), beginning with Bm, where (). This is an improvement over previous results on the maximal strings of zero residues of the Bell numbers. Similar results are obtained for the sequence of generalized Bell numbers An generated by . 相似文献
14.
Medha Dhurandhar 《Journal of Combinatorial Theory, Series B》1984,37(3):210-220
Here quadratic and cubic σ-polynomials are characterized, or, equivalently, chromatic polynomials of the graphs of order p, whose chromatic number is p ? 2 or p ? 3, are characterized. Also Robert Korfhage's conjecture that if σ2 + bσ + a is a σ-polynomial then is verified. In general, if σ(G) = Σ0naiσi is a σ-polynomial of a graph G, then an?2 is determined. 相似文献
15.
David Chillingworth 《Journal of Functional Analysis》1980,35(2):251-278
Let C be a Banach space, H a Hilbert space, and let F(C,H) be the space of C∞ functions f: C × H → R having Fredholm second derivative with respect to x at each (c, x) ?C × H for which ; here we write for . Say ? is of standard type if at all critical points of ?c it is locally equivalent (as an unfolding) to a quadratic form Q plus an elementary catastrophe on the kernel of Q. It is proved that if f?F (A × B, H) satisfies a certain ‘general position’ condition, and dim B ? 5, then for most a?A the function fo?F(B,H) is of standard type. Using this it is shown that those f?F(B,H) of standard type form an open dense set in F(B,H) with the Whitney topology. Thus both results are Hilbert-space versions of Thom's theorem for catastrophes in n. 相似文献
16.
V.B Headley 《Journal of Mathematical Analysis and Applications》1985,108(1):283-292
Let D(?) be the Doob's class containing all functions f(z) analytic in the unit disk Δ such that f(0) = 0 and lim on an arc A of ?Δ with length . It is first proved that if f?D(?) then the spherical norm ∥ f ∥ = supz?Δ, where C1 = limn→∞. Next, U represents the Seidel's class containing all non-constant functions f(z) bounded analytic in Δ such that almost everywhere. It is proved that inff?U∥f∥ = 0, and if f has either no singularities or only isolated singularities on ?Δ, then ∥f∥ ? C1. Finally, it is proved that if f is a function normal in Δ, namely, the norm ∥f∥< ∞, then we have the sharp estimate ∥fp∥ ? p∥f∥, for any positive integer p. 相似文献
17.
Let R = (r1,…, rm) and S = (s1,…, sn) be nonnegative integral vectors, and let (R, S) denote the class of all m × n matrices of 0's and 1's having row sum vector R and column sum vector S. An invariant position of (R, S) is a position whose entry is the same for all matrices in (R, S). The interchange graph G(R, S) is the graph where the vertices are the matrices in (R, S) and where two matrices are joined by an edge provided they differ by an interchange. We prove that when 1 ≤ ri ≤ n ? 1 (i = 1,…, m) and 1 ≤ sj ≤ m ? 1 (j = 1,…, n), G(R, S) is prime if and only if (R, S) has no invariant positions. 相似文献
18.
Albert L Wells 《Journal of Combinatorial Theory, Series A》1979,27(3):342-355
Let n and m be natural numbers, n ? m. The separation power of order n and degree m is the largest integer k = k(n, m) such that for every (0, 1)-matrix A of order n with constant linesums equal to m and any set of k 1's in A there exist (disjoint) permutation matrices P1,…, Pm such that A = P1 + … + Pm and each of the k 1's lies in a different Pi. Almost immediately we have 1 ? k(n, m) ? m ? 1, yet in all cases where the value of k(n, m) is actually known it equals m ? 1 (except under the somewhat trivial circumstances of k(n, m) = 1). This leads to a conjecture about the separation power, namely that k(n, m) = m ? 1 if . We obtain the bound , so that this conjecture holds for n ? 7. We then move on to latin squares, describing several equivalent formulations of the concept. After establishing a sufficient condition for the completion of a partial latin square in terms of the separation power, we can show that the Evans conjecture follows from this conjecture about the separation power. Finally the lower bound on k(n, m) allows us to show, after some calculations, that the Evans conjecture is true for orders n ? 11. 相似文献
19.
Hock Ong 《Linear algebra and its applications》1976,15(2):119-151
Let F be a field, F1 be its multiplicative group, and = {H:H is a subgroup of F1 and there do not exist a, b?F1 such that Ha+b?H}. Let Dn be the dihedral group of degree n, H be a nontrivial group in , and τn(H) = {α = (α1, α2,…, αn):αi?H}. For σ?Dn and α?τn(H), let P(σ, α) be the matrix whose (i,j) entry is αiδiσ(j) (i.e., a generalized permutation matrix), and . Let Mn(F) be the vector space of all n×n matrices over F and P(Dn, H) = {T:T is a linear transformation on Mn (F) to itself and T(P(Dn, H)) = P(Dn, H)}. In this paper we classify all T in P(Dn, H) and determine the structure of the group P(Dn, H) (Theorems 1 to 4). An expository version of the main results is given in Sec. 1, and an example is given at the end of the paper. 相似文献
20.
Robert L Miller 《Journal of Combinatorial Theory, Series A》1979,26(2):166-178
In this paper we show that two minimal codes 1 and 2 in the group algebra 2[G] have the same (Hamming) weight distribution if and only if there exists an automorphism θ of G whose linear extension to 2[G] maps 1 onto 2. If θ(M1) = M2, then 1 and 2 are called equivalent. We also show that there are exactly τ(l) inequivalent minimal codes in 2[G], where ? is the exponent of G, and τ(?) is the number of divisors of ?. 相似文献