Zobrazeno 1 - 10
of 44
pro vyhledávání: '"Gholamreza Omidi"'
Autor:
Leila Maherani, Gholamreza Omidi
Publikováno v:
پژوهشهای ریاضی, Vol 7, Iss 4, Pp 714-726 (2021)
For given graphs G1 and G2 the Ramsey number R(G1;G2), is the smallest positive integer n such that each blue-red edge coloring of the complete graph Kn contains a blue copy of G1 or a red copy of G2. In 1983, Erd}os conjectured that there is an abso
Externí odkaz:
https://doaj.org/article/ffa2b907515240f9939c1f217e6488a1
Autor:
Gholamreza Omidi, Khosro Tajbakhsh
Publikováno v:
Transactions on Combinatorics, Vol 3, Iss 2, Pp 31-33 (2014)
For a given hypergraph $H$ with chromatic number $chi(H)$ and with no edge containing only one vertex, it is shown that the minimum number $l$ for which there exists a partition (also a covering) ${E_1,E_2,ldots,E_l}$ for $E(H)$, such that the hyper
Externí odkaz:
https://doaj.org/article/841f54769d324c72a442e976c3402257
Autor:
Gholamreza Omidi
Publikováno v:
Combinatorics, Probability and Computing. 30:654-669
It has been conjectured that, for any fixed \[{\text{r}} \geqslant 2\] and sufficiently large n, there is a monochromatic Hamiltonian Berge-cycle in every \[({\text{r}} - 1)\]-colouring of the edges of \[{\text{K}}_{\text{n}}^{\text{r}}\], the comple
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::98d363d8574b3b5b73745992f827bcf0
https://doi.org/10.1017/s0963548320000243
https://doi.org/10.1017/s0963548320000243
Publikováno v:
Journal of Graph Theory. 88:507-520
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::878cc9d92abfb3d5cf44f53917032d84
https://doi.org/10.1002/jgt.22226
https://doi.org/10.1002/jgt.22226
Autor:
Maryam Shahsiah, Gholamreza Omidi
Publikováno v:
Discrete Applied Mathematics. 230:112-120
Gyarfas, Sarkozy and Szemeredi proved that the 2 -color Ramsey number R ( C n k , C n k ) of a k -uniform loose cycle C n k is asymptotically 1 2 ( 2 k − 1 ) n , generating the same result for k = 3 due to Haxell et al. Concerning their results, it
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::61d42c45b540e8bc5315632d3d6c3d13
https://doi.org/10.1016/j.dam.2017.04.046
https://doi.org/10.1016/j.dam.2017.04.046
Autor:
Leila Maherani, Gholamreza Omidi
Publikováno v:
Discrete Mathematics. 340:2043-2052
It has been conjectured that for any fixed r and sufficiently large n, there is a monochromatic Hamiltonian Berge-cycle in every (r1)-coloring of the edges of Knr, the complete r-uniform hypergraph on n vertices. In this paper, we show that the state
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::ad35d296384949986693f46ddf0e1df7
https://doi.org/10.1016/j.disc.2016.09.032
https://doi.org/10.1016/j.disc.2016.09.032
Autor:
Maryam Shahsiah, Gholamreza Omidi
Publikováno v:
Discrete Mathematics. 340:1426-1434
Recently, determining the Ramsey numbers of loose paths and cycles in uniform hypergraphs has received considerable attention. It has been shown that the $2$-color Ramsey number of a $k$-uniform loose cycle $\mathcal{C}^k_n$, $R(\mathcal{C}^k_n,\math
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::5012fcf430ecefd60a12fc6aa3be6633
https://doi.org/10.1016/j.disc.2016.09.024
https://doi.org/10.1016/j.disc.2016.09.024
For a graph $G$, a hypergraph $\mathcal{H}$ is a Berge copy of $G$ (or a Berge-$G$ in short), if there is a bijection $f : E(G) \rightarrow E(\mathcal{H})$ such that for each $e \in E(G)$ we have $e \subseteq f(e)$. We denote the family of $r$-unifor
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::00f20b16fe4b51be78cc2bdb63e3a050
http://arxiv.org/abs/1808.10434
http://arxiv.org/abs/1808.10434
Autor:
E.R. van Dam, Gholamreza Omidi
Publikováno v:
Journal of Algebraic Combinatorics, 47(4). Springer Netherlands
We generalize the concept of strong walk-regularity to directed graphs. We call a digraph strongly $$\ell $$ -walk-regular with $$\ell > 1$$ if the number of walks of length $$\ell $$ from a vertex to another vertex depends only on whether the first
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::f15ce111fddb927c9836e32ea485f430
https://doi.org/10.1007/s10801-017-0789-8
https://doi.org/10.1007/s10801-017-0789-8
Autor:
Gholamreza Omidi
Publikováno v:
Journal of Algebraic Combinatorics. 42:537-554
The spectral excess theorem, a remarkable result due to Fiol and Garriga, states that a connected regular graph with $$d+1$$d+1 distinct eigenvalues is distance-regular if and only if the average excess (the mean of the numbers of vertices at distanc
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::65a2cb3dc32e402029c905dc0fab2cad
https://doi.org/10.1007/s10801-015-0590-5
https://doi.org/10.1007/s10801-015-0590-5