Zobrazeno 1 - 10
of 85
pro vyhledávání: '"Yahya Ould Hamidoune"'
Autor:
Yahya Ould Hamidoune
Publikováno v:
Combinatorica. 39:1281-1315
The isoperimetric method is often useful for proving results regarding sumsets. Here, we introduce the notion of a hyper-atom into the method, which overcomes a previous weakness when dealing with atoms that are cosets. To show the utility of this ne
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::0d2b01e29eebaaa4850d2528b4c7990b
https://doi.org/10.1007/s00493-019-2429-5
https://doi.org/10.1007/s00493-019-2429-5
Autor:
Yahya Ould Hamidoune
Publikováno v:
Combinatorica. 33:217-230
Let A be a finite subset of a group G0 with |A−1A|≤2|A−2. We show that there are an element α∈A and a non-null proper subgroup H of G such that one of the following holds: x−1Hy⊂A−1A, for all x,y∈A not both in Hα xHy−1⊂AA−1, f
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::9749b652ff4c5776ce86d6d42494b79d
https://doi.org/10.1007/s00493-013-2731-6
https://doi.org/10.1007/s00493-013-2731-6
Publikováno v:
Recercat. Dipósit de la Recerca de Catalunya
instname
Repositorio Abierto de la UdL
Universitad de Lleida
instname
Repositorio Abierto de la UdL
Universitad de Lleida
We investigate the structure of a digraph having a transitive automorphism group where every cutset of minimal cardinality consists of all successors or all predecessors of some vertex. We give a complete characterization of vosperian arc-transitive
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::24a9ccb5f56c5cf3d9b563995c0897bf
https://doi.org/10.1007/s00373-011-1104-4
https://doi.org/10.1007/s00373-011-1104-4
Autor:
Yahya Ould Hamidoune
Publikováno v:
Combinatorics, Probability and Computing. 20:855-865
In this paper, we study certain pairings which are defined as follows: if A and B are finite subsets of an arbitrary group, a Wakeford–Fan–Losonczy pairing from B onto A is a bijection φ : B → A such that bφ(b) ∉ A, for every b ∈ B. The n
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::4cbb176781a9bb85f3f35f66d26dd806
https://doi.org/10.1017/s0963548311000459
https://doi.org/10.1017/s0963548311000459
Publikováno v:
Recercat. Dipósit de la Recerca de Catalunya
instname
UPCommons. Portal del coneixement obert de la UPC
Universitat Politècnica de Catalunya (UPC)
Digital.CSIC. Repositorio Institucional del CSIC
instname
UPCommons. Portal del coneixement obert de la UPC
Universitat Politècnica de Catalunya (UPC)
Digital.CSIC. Repositorio Institucional del CSIC
10 páginas.
For k prime and A a finite set of integers with |A|≥ 3(k − 1)2(k − 1)! we prove that |A + k · A| ≥ (k + 1)|A| − k(k + 2)/4 where k · A = {ka: a € A}. We also describe the sets for which equality holds.
Supported b
For k prime and A a finite set of integers with |A|≥ 3(k − 1)2(k − 1)! we prove that |A + k · A| ≥ (k + 1)|A| − k(k + 2)/4 where k · A = {ka: a € A}. We also describe the sets for which equality holds.
Supported b
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::bca850b18ab90558a2f68dc93c5c2afb
https://doi.org/10.1017/s0963548309990307
https://doi.org/10.1017/s0963548309990307
Autor:
Yahya Ould Hamidoune
Publikováno v:
Combinatorics, Probability and Computing. 17:793-798
Let G denote a finite abelian group of order n and Davenport constant D, and put m = n + D − 1. Let x = (x1,. . .,xm) ∈ Gm. Gao's theorem states that there is a reordering (xj1, . . ., xjm) of x such that Let w = (x1, . . ., wm) ∈ ℤm. As a co
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::3b5af09d3784556c7b9a13d5c1cc9106
https://doi.org/10.1017/s0963548308009425
https://doi.org/10.1017/s0963548308009425
Publikováno v:
Journal de Théorie des Nombres de Bordeaux. 20:125-130
Un resultat recent de Balandraud demontre que pour toute partie S d'un groupe abelien G, il existe un sous-groupe H non-trivial tel que l'inegalite |TS| ≤ |T| + |S| - 2 n'a lieu que si H ⊂ Stab(TS). On remarque que le theoreme de Kneser n'impliqu
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::2f2dd6ff9916da745869431d0ead9d4b
https://doi.org/10.5802/jtnb.618
https://doi.org/10.5802/jtnb.618
Autor:
Yahya Ould Hamidoune
Publikováno v:
Combinatorics, Probability and Computing. 17:61-66
Let Γ =(V,E) be a point-symmetric reflexive relation and let υ ∈ V such that |Γ(υ)| is finite (and hence |Γ(x)| is finite for all x, by the transitive action of the group of automorphisms). Let j ∈ℕ be an integer such that Γj(υ)∩ Γ−
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::2403b5c5fe8a9b29dc1dc33d8f36ed4b
https://doi.org/10.1017/s0963548307008620
https://doi.org/10.1017/s0963548307008620
Autor:
Yahya Ould Hamidoune
Publikováno v:
Annales de l’institut Fourier. 58:2007-2036
Soient G un groupe et X un sous-ensemble fini de G. La methode isoperimetrique etudie la fonction objective |(XB) \ X|, definie sur les parties X telles que |X| ≥ k et |G\(XB)| ≥ k, ou XB est le produit de X par B. Les inegalites additives decoul
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::0fef8910e9d388fbde1bfdfb8927c47b
https://doi.org/10.5802/aif.2404
https://doi.org/10.5802/aif.2404
Autor:
Yahya Ould Hamidoune, Domingo Quiroz
Publikováno v:
Combinatorics, Probability and Computing. 14:485-489
Let $G$ be a finite group of order $n$ and let $k$ be a natural number. Let $\{x_i : i\in I\}$ be a family of elements of $G$ such that $|I|= n+k-1$. Let $v$ be the most repeated value of the family. Let $ \{ \sigma_i : 1\leq i \leq k \} $ be a famil
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::39a143fc874ed196f88e405adbf8a565
https://doi.org/10.1017/s0963548305006814
https://doi.org/10.1017/s0963548305006814