Semigroups with the Erdös-Turán Property
A set X in a semigroup G has the Erdös-Turán property ET if, for any basis A of X, the representation function rA is ubounded, where rA(x) counts the number of representations of x as a product two elements in A. We show that, under some conditions, operations on binary vectors whose value at each c...
| Autores: | , |
|---|---|
| Tipo de recurso: | artículo |
| Fecha de publicación: | 2006 |
| País: | España |
| Institución: | Universitat Politècnica de Catalunya (UPC) |
| Repositorio: | UPCommons. Portal del coneixement obert de la UPC |
| Idioma: | inglés |
| OAI Identifier: | oai:upcommons.upc.edu:2117/405 |
| Acceso en línea: | https://hdl.handle.net/2117/405 |
| Access Level: | acceso abierto |
| Palabra clave: | Ramsey theory Number theory semigroups additive bases Ramsey theorem Ramsey, Teoria de Nombres, Teoria dels Classificació AMS::11 Number theory::11B Sequences and sets |
| Sumario: | A set X in a semigroup G has the Erdös-Turán property ET if, for any basis A of X, the representation function rA is ubounded, where rA(x) counts the number of representations of x as a product two elements in A. We show that, under some conditions, operations on binary vectors whose value at each coordinate depends only on neighbouring coordinates of the factors give rise to semigroups with the ET{property. In particular countable powers of semigroups with no mutually inverse elements have the ET{property. As a consequence, for each k there is N(k) such that, for every ¯nite subset X of a group G with X \ X¡1 = f1g, the representation function of every basis of XN ½ GN, N ¸ N(k), is not bounded by k. This is in contrast with the known fact that each p{elementary group admits a basis of the whole group whose representation function is bounded by an absolute constant |
|---|