منابع مشابه
Intersection Matrices Revisited
Several intersection matrices of s-subsets versus k-subsets of a v-set are introduced in the literature. We study these matrices systematically through counting arguments and generating function techniques. A number of new or known identities appear as natural consequences of this viewpoint; especially, use of the derivative operator d/dz and some related operators reveals some connections betw...
متن کاملFlexible Paxos: Quorum Intersection Revisited
Distributed consensus is integral to modern distributed systems. The widely adopted Paxos algorithm uses two phases, each requiring majority agreement, to reliably reach consensus. In this paper, we demonstrate that Paxos, which lies at the foundation of many production systems, is conservative. Specifically, we observe that each of the phases of Paxos may use non-intersecting quorums. Majority...
متن کاملEssentially Hermitian matrices revisited
The following case of the Determinantal Conjecture of Marcus and de Oliveira is established. Let A and C be hermitian n × n matrices with prescribed eigenvalues a1, . . . , an and c1, . . . , cn, respectively. Let κ be a non-real unimodular complex number, B = κC, bj = κcj for j = 1, . . . , n. Then det(A− B) ∈ co 8< : n Y j=1 (aj − bσ(j)); σ ∈ Sn 9= ; , where Sn denotes the group of all permut...
متن کاملEstimation under unknown correlation: covariance intersection revisited
This paper addresses the problem of obtaining a consistent estimate (or upper bound) of the covariance matrix when combining two quantities with unknown correlation. The combination is defined linearly with two gains. When the gains are chosen a priori, a family of consistent estimates is presented in the paper. The member in this family having minimal trace is said to be “family-optimal”. When...
متن کاملEnumeration of t-Designs Through Intersection Matrices
In this paper, we exploit some intersection matrices to empower a backtracking approach based on Kramer–Mesner matrices. As an application, we consider the interesting family of simple t-ðtþ 8; tþ 2; 4Þ designs, 1 t 4, and provide a complete classification for t 1⁄4 1; 4, as well as a classification of all non-rigid designs for t 1⁄4 2; 3. We also enumerate all rigid designs for t 1⁄4 2. The co...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: Journal of Combinatorial Designs
سال: 2012
ISSN: 1063-8539
DOI: 10.1002/jcd.21308