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تسجيل مستخدم جديدSuperfilters, Ramsey theory, and van der Waerdens Theorem
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Superfilters are generalized ultrafilters, which capture the underlying concept in Ramsey theoretic theorems such as van der Waerdens Theorem. We establish several properties of superfilters, which generalize both Ramseys Theorem and its variant for ultrafilters on the natural numbers. We use them to confirm a conjecture of Kov{c}inac and Di Maio, which is a generalization of a Ramsey theoretic result of Scheepers, concerning selections from open covers. Following Bergelson and Hindmans 1989 Theorem, we present a new simultaneous generalization of the theorems of Ramsey, van der Waerden, Schur, Folkman-Rado-Sanders, Rado, and others, where the colored sets can be much smaller than the full set of natural numbers.
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We prove a canonical polynomial Van der Waerdens Theorem. More precisely, we show the following. Let ${p_1(x),ldots,p_k(x)}$ be a set of polynomials such that $p_i(x)in mathbb{Z}[x]$ and $p_i(0)=0$, for every $iin {1,ldots,k}$. Then, in any colouring
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