共查询到20条相似文献,搜索用时 328 毫秒
2.
3.
4.
Let R, S and T be finite sets with , and . A code with covering radius 1 and minimum distance 2 is closely connected to a certain generalized partial Latin rectangle. We present various constructions of such codes and some lower bounds on their minimal cardinality . These bounds turn out to be best possible in many instances. Focussing on the special case we determine when r divides s, when , when s is large, relative to r, when r is large, relative to s, as well as . Finally, a table with bounds on is given. 相似文献
5.
6.
7.
8.
In this work we present an enumeration algorithm for the generation of all Steiner trees containing a given set W of terminals of an unweighted graph G such that , for a fixed positive integer k. The enumeration is performed within delay, where consequence of the algorithm is that the Steiner interval and the strong Steiner interval of a subset can be computed in polynomial time, provided that the size of W is bounded by a constant. 相似文献
9.
John Bamberg S.P. Glasby Luke Morgan Alice C. Niemeyer 《Journal of Pure and Applied Algebra》2018,222(10):2931-2951
Let be a prime. For each maximal subgroup with , we construct a d-generator finite p-group G with the property that induces H on the Frattini quotient and . A significant feature of this construction is that is very small compared to , shedding new light upon a celebrated result of Bryant and Kovács. The groups G that we exhibit have exponent p, and of all such groups G with the desired action of H on , the construction yields groups with smallest nilpotency class, and in most cases, the smallest order. 相似文献
10.
11.
《Journal de Mathématiques Pures et Appliquées》2005,84(9):1147-1172
Let be a function such that for , for constants . We consider spherically symmetric solutions of where g is a Schwarzschild or more generally a Reissner–Nordström metric, and such that ϕ and ∇ϕ are compactly supported on a complete Cauchy surface. It is proven that for , such solutions do not blow up in the domain of outer communications, provided the initial data are small. Moreover, , where v denotes an Eddington–Finkelstein advanced time coordinate. 相似文献
13.
《Discrete Mathematics》2007,307(17-18):2226-2234
14.
15.
17.
A. Mimouni 《Journal of Algebra》2009,321(5):1497-1509
In this paper, we will present new developments in the study of the links between the cardinality of the sets of all overrings of R, of all semistar operations of finite character when finite to the Krull dimension of an integral domain R. In particular, we prove that if , then R has at most distinct maximal ideals. Moreover, R has exactly maximal ideals if and only if . In this case R is a Prüfer domain with exactly two maximal ideals and Y-graph spectrum. We also give a complete characterizations for local domains R such that , and nonlocal domains R with for , , and . Examples to illustrate the scopes and limits of the results are constructed. 相似文献
18.
The Cauchy-Davenport theorem states that, if p is prime and A, B are nonempty subsets of cardinality r, s in , the cardinality of the sumset is bounded below by ; moreover, this lower bound is sharp. Natural extensions of this result consist in determining, for each group G and positive integers , the analogous sharp lower bound, namely the function Important progress on this topic has been achieved in recent years, leading to the determination of for all abelian groups G. In this note we survey the history of earlier results and the current knowledge on this function. 相似文献
19.