搜索结果: 1-11 共查到“组合数学 E-sets”相关记录11条 . 查询时间(0.03 秒)
Lattice-point generating functions for free sums of convex sets
Lattice-point generating functions free sums of convex sets Combinatorics
2012/7/11
Let $\J$ and $\K$ be convex sets in $\R^{n}$ whose affine spans intersect at a single rational point in $\J \cap \K$, and let $\J \oplus \K = \conv(\J \cup \K)$. We give expressions for the generating...
Blocking Sets of Index Three
Redei Blocking Sets Projective Triangle Projective Triad Combinatorics
2012/6/15
In this note we will provide proofs for the various statements that have been made in the literature about blocking sets of index three. Our aim is to clarify what is known about the characterization ...
Counting independent sets of a fixed size in graphs with a given minimum degree
graphs given minimum degree independent sets Combinatorics
2012/4/16
Galvin showed that for all fixed $\delta$ and sufficiently large $n$, the $n$-vertex graph with minimum degree $\delta$ that admits the most independent sets is the complete bipartite graph $K_{\delta...
Strongly Regular Cayley Graphs, Skew Hadamard Difference Sets, and Rationality of Relative Gauss Sums
strongly regular graph skew Hadamard difference set relative Gauss sum
2012/3/1
In this paper, we give constructions of strongly regular Cayley graphs and skew Hadamard difference sets. Both constructions are based on choosing cyclotomic classes in finite fields, and our results ...
The 1/3-2/3 conjecture for $N$-free ordered sets
Ordered set Linear extension N-free Balanced pair 1/3-2/3 Conjecture
2011/9/22
Abstract: A balanced pair in a finite ordered set $P=(V,\leq)$ is a pair $(x,y)$ of elements of $V$ such that the proportion of linear extensions of $P$ that put $x$ before $y$ is in the real interval...
On a sparse random graph with minimum degree {three}: Likely Posa's sets are large
random sparse graphs degrees longest path Posa sets
2011/9/20
Abstract: We consider the likely size of the endpoint sets produced by Posa rotations, when applied to a longest path in a random graph with $cn,\,c\geq 2.7$ edges that is conditioned to have minimum ...
Distance sets of universal and Urysohn metric spaces
Distance sets of universal Urysohn metric spaces Combinatorics
2011/9/20
Abstract: A metric space $\mathrm{M}=(M;\de)$ is {\em homogeneous} if for every isometry $f$ of a finite subspace of $\mathrm{M}$ to a subspace of $\mathrm{M}$ there exists an isometry of $\mathrm{M}$...
Sets with High Volume and Low Perimeter
High Volume Low Perimeter Combinatorics Number Theory
2011/9/9
Abstract: In this paper, we consider a certain variation of the "isoperimetric problem" adopted for subsets of nonnegative integers. More specifically, we explore the sequence P(n) as described in OEI...
Abstract: Fix integers $b>a\geq1$ with $g:=\gcd(a,b)$. A set $S\subseteq\mathbb{N}$ is \emph{$\{a,b\}$-multiplicative} if $ax\neq by$ for all $x,y\in S$. For all $n$, we determine an $\{a,b\}$-multipl...
Optimal sets for a class of minimization problems with convex constraints
Convex geometry shape optimization isoperimetric inequalities length
2011/2/24
We look for the minimizers of the functional J( ) = | | − P( ) among planar convex domains constrained to lie into a given ring.
Cyclic and Quasi-Cyclic LDPC Codes on Row and Column Constrained Parity-Check Matrices and Their Trapping Sets
Quasi-Cyclic LDPC Codes on Row Column Constrained Parity-Check Matrices Their Trapping Sets
2011/2/21
This paper is concerned with construction and structural analysis of both cyclic and quasi-cyclic codes, particularly LDPC codes. It consists of three parts. The first part shows that a cyclic code gi...