منابع مشابه
Disjunctive Rado numbers
If L1 and L2 are linear equations, then the disjunctive Rado number of the set {L1, L2} is the least integer n, provided that it exists, such that for every 2-coloring of the set {1, 2, . . . , n} there exists a monochromatic solution to either L1 or L2. If such an integer n does not exist, then the disjunctive Rado number is infinite. In this paper, it is shown that for all integers a 1 and b ...
متن کاملOn Erdös-Rado Numbers
In this paper new proofs of the Canonical Ramsey Theorem, which originally has been proved by ErdSs and Rado, are given. These yield improvements over the known bounds for the arising Erd6s-Rado numbers ER(k; l), where the numbers ER(k; l) are defined as the least positive integer n such that for every partition of the k-element subsets of a totally ordered n-element set X into an arbitrary num...
متن کاملBetter Bounds on Rado Numbers
This was first proven by van der Warden [6]. See the books by Graham, Rothchild, and Spencer [3], Landman and Robertson [4] or the free on-line book of Gasarch, Kruskal, Parrish [1] for the proof in English. This proof gives enormous upper bounds on the numbers W (k, c) that are not primitive recursive. Shelah [5] gave an alternative proof that yields primitive recursive upper bounds. All of th...
متن کاملTwo Color Off-diagonal Rado-type Numbers
We show that for any two linear homogeneous equations E0, E1, each with at least three variables and coefficients not all the same sign, any 2-coloring of Z+ admits monochromatic solutions of color 0 to E0 or monochromatic solutions of color 1 to E1. We define the 2-color off-diagonal Rado number RR(E0, E1) to be the smallest N such that [1, N ] must admit such solutions. We determine a lower b...
متن کاملDisjunctive !-Words and Real Numbers
An !-word p over a nite alphabet is called disjunctive if every nite word over occurs as a subword in p. A real number is called disjunctive to base a if it has a disjunctive a-adic expansion. For every pair of integers a; b 2 such that there exist numbers disjunctive to base a but not to base b we explicitly construct very simple examples of such numbers. General versions of the following resu...
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ژورنال
عنوان ژورنال: Journal of Combinatorial Theory, Series A
سال: 2005
ISSN: 0097-3165
DOI: 10.1016/j.jcta.2005.02.007