Large recurrence of the polynomial Van der Waerden's theorem and its application in Ramsey theory (2401.10550v3)

Abstract: Recently M. Di Nasso and M. Ragosta proved an exponential version of Hindman's finite sum theorem: for every finite partition of $\mathbb{N}$, there exists a monochromatic Hindman tower of a single sequence. They used the stronger version of Furstenberg's Central Sets Theorem and the theory of ultrafilters to prove their results. In this article, we prove these patterns are abundant by considering two-fold extensions of the Di Nasso-Ragosta theorem. We prove that each term of this pattern can be chosen from a finite set of any given length, consisting of a multiplicative $IP_r$ (that we will define later) set and a set consisting of geometric progression (sets containing both arithmetic and geometric progression) of finite length. To prove our result, first, we improve the size of the recurrence set of V. Bergelson and A. Leibmann's polynomial Van der Waerden's Theorem, and then we study its two-fold applications. First, we study monochromatic patterns involving polynomials over sum sets in additive piecewise syndetic sets. Then in the second, applying methods of induction, we construct infinitary patterns involving a two-fold improvement of the Di Nasso-Ragosta theorem. Then we study the properties of some special classes of ultrafilters witnessing variants of these patterns. Throughout our article, we use the methods from the Algebra of the Stone-\v{C}ech-Compactification of discrete semigroups (for details see [N. Hindman and D. Strauss: Algebra in the Stone-\v{C}ech compactification. Walter de Gruyter& Co., Berlin, 2012.]).