Results 111 to 120 of about 57,717 (241)

Bounds for the Zero Forcing Number of Graphs with Large Girth

Theory and Applications of Graphs, 2015
The zero-forcing number, Z(G) is an upper bound for the maximum nullity of all symmetric matrices with a sparsity pattern described by the graph. A simple lower bound is δ ≤ Z(G) where δ is the minimum degree.
Randy Davila, Franklin Kenter
doaj   +1 more source

3-regular matchstick graphs with given girth [PDF]

, 2009
We consider 3-regular planar matchstick graphs, i. e. those whichhave a planar embedding such that all edge lengths are equal, with given girth g. For girth 3 it is known that such graphs exist if and only if the number of vertices n is an even integer ...
S. Kurz, MAZZUOCCOLO, Giuseppe
core  

Topological Minors in Graphs of Large Girth [PDF]

, 1988
We prove that every graph of minimum degree at least r and girth at least 186 contains a subdivision of K_r+1 and that for r ≥ 435 a girth of at least 15 suces.
Deryk Osthus, Daniela Kühn
core  

Injective coloring of planar graphs without intersecting 5-cycles

上海师范大学学报. 自然科学版
An injective coloring is a vertex coloring such that any two vertices sharing a common neighbor receive distinct colors. Let χi (G) be the injective chromatic number of a graph G.
CHEN Hongyu, PAN Lina
doaj   +1 more source

On the Girth of Tanner QC-LDPC Cycle Codes: An Algebraic Number Theory Approach

Axioms
Tanner quasi-cyclic low-density parity-check (QC-LDPC) codes form an important family of structured LDPC codes with favorable girth properties. This paper studies the girth of Tanner (2, L)-regular QC-LDPC codes (referred to as Tanner QC-LDPC cycle codes)
Haipeng Yu, Manjie Zhou, Zhongyang Yu, Mengmeng Xu, Hengzhou Xu   +4 more
doaj   +1 more source

Convolutional cylinder-type block-circulant cycle codes [PDF]

Transactions on Combinatorics, 2013
In this paper, we consider a class of column-weight two quasi-cyclic low-density paritycheck codes in which the girth can be large enough, as an arbitrary multiple of 8. Then we devote a convolutional form to these codes, such that their generator matrix
Mohammad Gholami, Mehdi Samadieh
doaj  

LDPC Codes on Balanced Incomplete Block Designs: Construction, Girth, and Cycle Structure Analysis

Entropy
In this paper, we investigate the cycle structure inherent in the Tanner graphs of low-density parity-check (LDPC) codes constructed from balanced incomplete block designs (BIBDs).
Hengzhou Xu, Xiaodong Zhang, Mengmeng Xu, Haipeng Yu, Hai Zhu   +4 more
doaj   +1 more source

QC-LDPC Codes Construction by Concatenating of Circulant Matrices as Block-Columns

International Journal of Information and Communication Technology Research, 2016
In this paper a new low complexity method for constructing binary quasi-cyclic low-density parity-check (QC-LDPC) codes is introduced. In the proposed method, each block-column of the parity check matrix H is made by a circulant matrix in a way that the ...
Mohammad Hesam Tadayon, Mohammad Mohammadi   +1 more
doaj  

Tight factorizations of girth-$g$-regular graphs [PDF]

Girth-regular graphs with equal girth, regular degree and chromatic index are studied for the determination of 1-factorizations with each 1-factor intersecting every girth cycle.
Dejter, Italo J.
core   +1 more source

Minors in graphs of large θr-girth [PDF]

, 2017
For every r∈N, let θr denote the graph with two vertices and r parallel edges. The θr-girth of a graph G is the minimum number of edges of a subgraph of G that can be contracted to θr.
Sau, I., Thilikos, D.M., Raymond, J.-F., Chatzidimitriou, D.   +3 more
core