activity
20102023
most citedEnumeration of bigrassmannian permutations below a permutation in Bruhat order

5 citations · 9 across the 20 of their papers we have counts for

collaborators

20 papers

math.NT2023

Ramanujan-Shen's differential equations for Eisenstein series of level 2

Masato Kobayashi

Ramanujan (1916) and Shen (1999) discovered differential equations for classical Eisenstein series. Motivated by them, we derive new differential equations for Eisenstein series of…

math.NT2023

Applications of Ramanujan's work on Eisenstein series

Masato Kobayashi

Ramanujan (1916) expressed quotients of certain q-series as polynomials of Eisenstein series of degree 2, 4, 6 and derived the famous Ramanujan's differential equations. We continu…

math.NT2022

New recurrences for divisor sum functions and triangular numbers

Masato Kobayashi

Euler discovered recurrence for divisor sum functions as a consequence of the pentagonal numbers theorem. With similar idea and also motivated by Ewell's work in 1977, we prove new…

math.NT2022

Values of zeta-one functions at positive even integers

Masato Kobayashi, Shunji Sasaki

Motivated by Euler-Goldbach and Shallit-Zikan theorems, we introduce zeta-one functions with infinite sums of as an analogy of the Riemann zeta function. Then we comput…

math.NT2021

From Basel Problem to multiple zeta values

Masato Kobayashi

We show many consequences of the proof of Basel problem by Boo Rim Choe (1987) to central binomial series, multiple zeta values and some other multiple sums. The main idea is to ev…

math.NT2021

Integral Evaluation of Odd Euler Sums, Multiple -Value and Multiple Zeta Value

Sarth Chavan, Masato Kobayashi, Jorge Layja

We construct an analytic approach to evaluate odd Euler sums, multiple zeta value and multiple -value . Moreover, we also conjectur…

math.NT2021

Integral representations for local dilogarithm and trilogarithm functions

Masato Kobayashi

We show new integral representations for dilogarithm and trilogarithm functions on the unit interval. As a consequence, we also prove (1) new integral representations for Apery, Ca…

math.CO2021★ 2 cited

Matrix representation of meet-irreducible discrete copulas

Masato Kobayashi

Following Aguiló-Suñer-Torrens (2008), Kolesárová-Mesiar-Mordelová-Sempi (2006) and Mayor-Suñer-Torrens (2005), we continue to develop a theory of matrix representation for discret…

math.NT2021★ 1 cited

New relations on zeta and functions

Masato Kobayashi

We prove new relations on zeta function at even arguments and Dirichlet function at odd. The key idea is to make use of the Taylor series and partial fraction decomposition of…

math.NT2021

Möbius functions of higher rank and Dirichlet series

Masato Kobayashi

We introduce Möbius functions of higher rank, a new class of arithmetic functions so that the classical Möbius function is of rank 2. With this idea, we evaluate Dirichlet series o…

math.NT2021

Integral representations for with the inverse sine function

Masato Kobayashi

We show four new integral representations for as a reformulation of Ewell (1990) and Yue-Williams (1993) with the inverse sine function and Wallis integral. As a consequence…

math.CO2019★ 1 cited

A new refinement of Euler numbers on counting alternating permutations

Masato Kobayashi

At a crossroads of calculus and combinatorics, the generating function of secant and tangent numbers (Euler numbers) provides enumeration of alternating permutations. In this artic…

math.CO2019

Weighted counting of Bruhat paths by shifted -polynomials

Masato Kobayashi

We revisit -polynomials with introducing the new idea ``shifted -polynomials" (or Bruhat weight) for all Bruhat intervals in finite Coxeter groups. Then, we apply these polyn…

math.CO2019

Construction of double coset system of a Coxeter group and its applications to Bruhat graphs

Masato Kobayashi

We develop combinatorics of parabolic double cosets in finite Coxeter groups as a follow-up of recent articles by Billey-Konvalinka-Petersen-Slofstra-Tenner and Petersen. (1) We co…

math.CO2019

Weighted counting of inversions on alternating sign matrices

Masato Kobayashi

We extend the author's formula (2011) of weighted counting of inversions on permutations to the one on alternating sign matrices. The proof is based on the sequential construction…

math.CO2019

A directed graph structure of alternating sign matrices

Masato Kobayashi

We introduce a new directed graph structure into the set of alternating sign matrices. This includes Bruhat graph (Bruhat order) of the symmetric groups as a subgraph (subposet). D…

math.CO2019

Enumerative combinatorics on determinants and signed bigrassmannian polynomials

Masato Kobayashi

As an application of linear algebra for enumerative combinatorics, we introduce two new ideas, signed bigrassmannian polynomials and bigrassmannian determinant. First, a signed big…

math.CO2018

Bruhat order and graph structures of lower intervals in Coxeter groups

Masato Kobayashi

We show that any lower Bruhat interval in a Coxeter group is a disjoint union of certain two-sided cosets as a consequence of Lifting Property and Subword Property. Furthermore, we…

math.CO2012

Inequalities on Bruhat graphs, R- and Kazhdan-Lusztig polynomials

Masato Kobayashi

From a combinatorial perspective, we establish three inequalities on coefficients of - and Kazhdan-Lusztig polynomials for crystallographic Coxeter groups: (1) Nonnegativity of…

math.CO2010★ 5 cited

Enumeration of bigrassmannian permutations below a permutation in Bruhat order

Masato Kobayashi

In theory of Coxeter groups, bigrassmannian elements are well known as elements which have precisely one left descent and precisely one right descent. In this article, we prove for…