arXiv subjects
Publications and source records attributed to Sayan Goswami.
Inspired by the paper [1] of V. Bergelson, John H.Johnson Jr., J. Moreira, we formulate an abstract version of image partition regularity. To establish the result we have used a variant of first entry condition and for infinite case we contained our work to Milliken-Taylor system.
In a recent work, N. Hindman, D. Strauss and L. Zamboni have shown that the Hales-Jewett theorem can be combined with a sufficiently well behaved homomorphisms. In this paper we will show that those combined extensions can be made if we replace the alphabet by an increasing sequence of alphabets, infact it holds for some Ramsey theoretic small sets. To obtained this we achieved some interesting configurations.
In this paper we will systematically study the preservation of the notion of largeness of sets, arises from the algebraic structure of Stone-Cech compactification, under homomorphism and difference group. Some of these results were studied previously using algebra of Stone-Cech compactification. But our approach is purely combinatorial.
The famous van der Waerden theorem states that if partition N into finitely many cells then one of them will contain arbitrary length arithmetic progressions. It has a polynomial version also. In this article we will prove the near 0 version of the polynomial van der Waerden theorem which was unsolved, using combinatorics.
There is a long history of studying Ramsey theory using the algebraic structure of Stone-Cech compactification of discrete semigroup. It has been shown that various Ramsey theoretic structures are contained in different algebraic large sets. In this article we will study elementary characterization of essential F sets. And also study the mixing properties arises from essential F sets.
H. Furstenberg introduced the notion of central set in terms of topological dynamics and established the central set theorem. The essence of central set theorem is that it is the simultaneous extension of van der Waerden's theorem and Hindman's theorem. Later V. Bergelson and N. Hindman established a connection between central sets and the algebra of Stone-cech compactification and proved that the central sets are the member of minimal idempotent ultrafilter of discrete semigroup. In some subsequent papers the central set theorem has been studied more deeply and some generalizations has been established. Those works use the techniques of Stone-Cech compactification of discrete semigroup. In this work we will prove central set theorem via combinatorial approach using the combinatorial characterization of central set established by N. Hindman, A. Malkeki and D. Strauss. Though we will use the combinatorial approach but the technique of the proof is similar to the proof of D. De, N. Hindman, D. Strauss.
N. Hindman and D. Strauss had shown that, for discrete semigroups, the cartesian product of two central sets are central. They also proved that the product of J- sets and C-sets are also J-set and C-set and characterized when the infnite product of these sets are preserved. To prove these results they used the algebraic structure of Stone-Cech compactification of discrete semigroups. In this work we will give a combinatorial proof of the preserveness of those large sets under fnite cartesian product.
N. Hindman and I. Leader introduced the set of ultrafilters 0+ on (0,1) and characterize smallest ideal of (0+,+) and proved the Central Set Theorem near zero. Recently Polynomial Central Set Theorem has been proved by V. Bergelson, J. H. Johnson Jr. and J. Moreira. In this article, we will prove Polynomial Central Set Theorem near zero.
Furstenberg and Glasner proved that for an arbitrary k in N, any piecewise syndetic set contains k term arithmetic progression and such collection is also piecewise syndetic in Z. They used algebraic structure of beta N. The above result was extended for arbitrary semigroups by Bergelson and Hindman, again using the structure of Stone-Cech compactification of general semigroup. Beiglbock provided an elementary proof of the above result and asked whether the combinatorial argument in his proof can be enhanced in a way which makes it applicable to a more abstract setting. In this work we provide a positive answer to Beiglbock question for commutative semigroup.
Furstenberg and Glasner proved that for an arbitrary k in N, any piecewise syndetic set contains k length arithmetic progression and such collection is also piecewise syndetic in Z: They used algebraic structure of beta N. The above result was extended for arbitrary semigroups by Bergelson and Hindman, again using the structure of Stone-Cech compactification of general semigroup. However they provided the abundances for various types of large sets. But the abundances in in many large sets is still unknown. In this work we will provide the abundance in Quasi Central sets, J-sets and C-sets.
Furstenberg, Glasscock, Bergelson, Beiglboeck have been studied abundance in arithmatic progression on various large sets like piecewise syndetic, central, thick, etc. but also there are so many sets in which abundance in progression is still unsettled like J-sets, C-sets, D-sets etc. But all of these sets have a common property that they contains arbitrary length of arithmatic progressions. These type of sets are called sets of A.P. rich, we have given an elementary proof of abundance of those sets.
Furstenberg and Glasner proved that for an arbitrary k in N, any piecewise syndetic set contains k term arithmetic progressions and such collection is also piecewise syndetic in Z: They used algebraic structure of beta N. The above result was extended for arbitrary semigroups by Bergelson and Hindman, again using the structure of Stone-Cech compactification of general semigroup. Beiglboeck provided an elementary proof of the above result and asked whether the combinatorial argument in his proof can be enhanced in a way which makes it applicable to a more abstract setting. In a recent work the second author of this paper and S.Jana provided an affirmative answer to Beiglboeck's question for countable commutative semigroup. In this work we will extend the result of Beiglboeck in different type of settings.
We estimate size of recurrence of an action of a nilpotent group by homeomorphisms of a compact space for polynomial mappings into a nilpotent group form the partial semigroup $(\mathcal{P}_{f}(\mathbb{N}),\uplus)$. To do this we have used algebraic structure of the Stone-Čech copactification partial semigroup and that of the given nilpotent group.