3-color Schur numbers

Let k ≥ 3 be an integer, the Schur number Sk(3) is the least positive integer, such that for every 3-coloring of the integer interval [1, Sk(3)] there exists a monochromatic solution to the equation x1+ · · · + xk= xk+1, where xi , i = 1, . . . , k need not be distinct. In 1966, a lower bound of Sk(...

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Detalhes bibliográficos
Autores: Boza Prieto, Luis, Marín Sánchez, Juan Manuel, Revuelta Marchena, María Pastora, Sanz Domínguez, María Isabel
Tipo de documento: artigo
Estado:Versión enviada para evaluación y publicación
Data de publicação:2019
País:España
Recursos:Universidad de Sevilla (US)
Repositório:idUS. Depósito de Investigación de la Universidad de Sevilla
OAI Identifier:oai:idus.us.es:11441/135995
Acesso em linha:https://hdl.handle.net/11441/135995
https://doi.org/10.1016/j.dam.2018.06.030
Access Level:Acceso aberto
Palavra-chave:Schur numbers
Sum-free sets
n-coloring
Monochromatic solution
Descrição
Resumo:Let k ≥ 3 be an integer, the Schur number Sk(3) is the least positive integer, such that for every 3-coloring of the integer interval [1, Sk(3)] there exists a monochromatic solution to the equation x1+ · · · + xk= xk+1, where xi , i = 1, . . . , k need not be distinct. In 1966, a lower bound of Sk(3) was established by Znám (1966). In this paper, we determine the exact formula of Sk(3) = k 3 + 2k 2 − 2, finding an upper bound which coincides with the lower bound given by Znám (1966). This is shown in two different ways: in the first instance, by the exhaustive development of all possible cases and in the second instance translating the problem into a Boolean satisfiability problem, which can be handled by a SAT solver.