Zobrazeno 1 - 10
of 23
pro vyhledávání: '"N. Zagaglia Salvi"'
Publikováno v:
Aequationes mathematicae. 92:671-682
The partition graph of a positive integer n, \(P_n\), is the graph whose vertices are the cyclic compositions of n and two vertices are adjacent if one composition is obtained from the other one by replacing two cyclically consecutive parts by their
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::fcfbef003266f4168d8cd11b29df632f
https://doi.org/10.1007/s00010-018-0554-7
https://doi.org/10.1007/s00010-018-0554-7
Autor:
A. Kramer, N. Zagaglia Salvi
Publikováno v:
European Journal of Combinatorics. 31(2):589-597
In this paper we investigate an isomorphism σ between a directed de Bruijn digraph B(2,n) and its converse, which is the digraph obtained from B(2,n) by reversing the direction of all its arcs. A cycle C is said to be σ-self-converse when the cycle
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::5255c2f00d4e1111013eb34824aa58a9
Two sequences (a1, a2, . . . , an) and (b1, b2, . . . , bn), sharing n − 1 elements, are said disarranged if for every subset Q ⊆ [n], the sets {ai | i ∈ Q} and {bi | i ∈ Q} are different. In this paper we investigate properties of these pair
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::60507a589021ce76a42008d8f3ae4570
http://hdl.handle.net/11311/1011979
http://hdl.handle.net/11311/1011979
Autor:
Francesco Regonati, N. Zagaglia Salvi
Publikováno v:
Czechoslovak Mathematical Journal. 44:315-323
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::db0e9d6833e747b3c547bd39042d0899
https://doi.org/10.21136/cmj.1994.128459
https://doi.org/10.21136/cmj.1994.128459
Autor:
N. Zagaglia Salvi
Publikováno v:
Discrete Mathematics. 155:267-269
A finite family of pairwise intersecting r-sets is a maximal r-clique if it cannot be extended to another r-clique by adding a new r-set. It is intersection critical if it is not possible to replace any edge by some of its proper subsets, without vio
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::be1f27f886d3037930b570a870bd8d4a
https://doi.org/10.1016/0012-365x(94)00391-u
https://doi.org/10.1016/0012-365x(94)00391-u
Autor:
N. Zagaglia Salvi
Publikováno v:
Journal of Graph Theory. 17:589-591
Let λ(G) be the line-distinguishing chromatic number and x′(G) the chromatic index of a graph G. We prove the relation λ(G) ≥ x′(G), conjectured by Harary and Plantholt. © 1993 John Wiley & Sons, Inc.
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::598f5cd767ca2ed041fbd35b3d06ccc9
https://doi.org/10.1002/jgt.3190170504
https://doi.org/10.1002/jgt.3190170504
Publikováno v:
Linear Algebra and its Applications. :153-162
A characterization of a class of symmetric (0, 1) matrices A such that AP is a symmetric matrix too, where P is a permutation matrix, is given, and an application to double coverings of graphs is considered.
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::e1fe669a7873254138edd42aeed1ffa5
Publikováno v:
Linear Algebra and its Applications. (1):367-375
In this paper we investigate generalized circulant permutation matrices of composite order. We give a complete characterization of the order and the structure of symmetric generalized k -circulant permutation matrices in terms of circulant and retroc
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::ba2479395491f305d1faac1dabb6ed18
Publikováno v:
Discrete Mathematics. (22):3241-3245
Let Bn be the binary de Bruijn digraph of order n and W the quotient set of the set of vertices of Bn with respect to the equivalence relation of rotation. Let G be the graph which has W as the set of vertices and in which two elements C and H are ad
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::63e20e7298aa61e005aa7e322a62a61e
Autor:
N. Zagaglia Salvi
Summary In this paper we determine some properties concerning a (v, k, λ)-difference set when v is even. In particular it is proved in certain cases the non-existence of circulant Hadamard matrices.
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::0989211f55e005bc2ad3699556365a8c
https://doi.org/10.1016/s0167-5060(08)70271-1
https://doi.org/10.1016/s0167-5060(08)70271-1