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Himadri Mukherjee

Publications and source records attributed to Himadri Mukherjee.

At least 19 recordsLinked to original sources
arXiv2026

Simultaneous triangularization over max-algebras

The purpose of this article is to investigate triangularization and simultaneous triangularization of matrices over max algebras using graph theoretic methods. We establish a connection between commutators and commutants with simultaneous triangularization over max algebras. We also define the notion of characteristic polynomial of a collection in terms of the tropical determinant and determine when it can be written as a product of linear terms. Algorithms for all of the above are also brought out.

math.RA↗
arXiv2025

Assessing Skew Normality in Marks Distribution, a Comparative Analysis of Shapiro Wilk Tests

This paper investigates the distribution of marks obtained by students across multiple courses to explore whether the data conforms to a skew-normal distribution. Traditional methods for assessing normality, such as the Shapiro Wilk test, often reject normality in datasets with evident skewness. To address this, we apply a modified Shapiro Wilk test tailored for skew-normal distributions, as described in the literature, to evaluate the suitability of skew-normal models for these datasets. The analysis includes both classical and modified tests, complemented by visualizations such as histograms and Q-Q plots of transformed data. Our findings highlight the relevance of using specialized statistical methods for skew normality, offering valuable insights into the characteristics of academic performance data. This study provides a framework for robust statistical analysis in educational research, emphasizing the need to account for distributional properties when analyzing student performance metrics.

stat.ME↗
arXiv2024

A Canonical Form for Max Plus Symmetric Matrices and Applications

We develop a canonical form for congruence of max plus symmetric matrices. We use the same canonical form to get results in the generalized eigenvector problem. We have also utilized the canonical form to find all symmetric matrices that commute with a given symmetric matrix.

math.RA↗
arXiv2024

An inequality generalizing $AM \geq GM$ and $AM \geq HM$

Aim of this article is to prove the inequality $n \sum_{i=1}^{n} a_ib_i \leq \sum_{i=1}^{n} a_i \sum_{i=1}^n b_i$ when $a_i$ are $n$ increasing positive real numbers and $b_i$ are $n$ decreasing real numbers. We also prove generalizations of this result.

math.CO↗
arXiv2024

Tropical Matrix Exponential

In this article, we introduce an exponential for tropical matrices and show that this series is essential for the analysis of certain kinds of stability in discrete event dynamic systems. A notion of a generalised eigenvector is introduced to discuss this kind of stability and prove it exists at most in the order of $1,p/2,p$, where $p$ is the period of the corresponding matrix. Thus characterizing the generalised eigenvectors of all powers of the matrix. Also, a sufficient condition is proved for the exponential of a matrix to be robust.

math.RA↗
arXiv2024

Solutions to a system of Yang-Baxter matrix equations

In this article, a system of Yang-Baxter-type matrix equations is studied, $XAX=BXB$, $XBX=AXA$, which "generalizes" the matrix Yang-Baxter equation and exhibits a broken symmetry. We investigate the solutions of this system from various geometric and topological points of view. We analyze the existence of doubly stochastic solutions and intertwining solutions to the system and describe the conditions for their existence. Furthermore, we characterize the case when $A$ and $B$ are idempotent orthogonal complements. i.e., $A^2 =A, B^2= B, AB = BA =0$. We also completely characterize the set of solutions for $n=2$ using commutative algebraic techniques.

math.RA↗
arXiv2024

The First Syzygy of Hibi Rings Associated with Planar distributive lattices

Let $\mathcal{L}$ be a finite distributive lattice and $S=K[x_α: α\in \mathcal{L}]$ be a polynomial ring over a field $K$ and $I=\langle x_αx_β- x_{α\vee β} x_{α\wedgeβ} : α\nsim β,α,β\in {\mathcal{L}} \rangle$ an ideal of $S$. In this article we describe the first syzygy of the Hibi ring $R[\mathcal{L}]=S/I$, for a planar distributive lattice $\mathcal{L}$. We also derive an exact formula for the first Betti number of a planar distributive lattice. We give a characterization of planar distributive lattices for which the first syzygy is linear.

math.AC↗
arXiv2024

On Structural and Spectral Properties of Distance Magic Graphs

A graph $G=(V,E)$ is said to be distance magic if there is a bijection $f$ from a vertex set of $G$ to the first $|V(G)|$ natural numbers such that for each vertex $v$, its weight given by $\sum_{u \in N(v)}f(u)$ is constant, where $N(v)$ is an open neighborhood of a vertex $v$. In this paper, we introduce the concept of $p$-distance magic labeling and establish the necessary and sufficient condition for a graph to be distance magic. Additionally, we introduce necessary and sufficient conditions for a connected regular graph to exhibit distance magic properties in terms of the eigenvalues of its adjacency and Laplacian matrices. Furthermore, we study the spectra of distance magic graphs, focusing on singular distance magic graphs. Also, we show that the number of distance magic labelings of a graph is, at most, the size of its automorphism group.

math.CO↗
arXiv2024

On the Linear Algebraic Monoids Associated to Congruence of Matrices

This paper discusses the generalized congruence equation $X^tAX=B$, for $X \in M_n(k)$ over any field $k$, through the action of monoid $Sol_A \times Sol_B := \{X \ | \ X^tAX = A\} \times \{X \ | \ X^tBX = B\}$. We have completely characterized for what matrices $A$, the monoid $Sol_A$ is a Lie group. We have given the structure of the Lie group $Sol_A$ and $Sol_{A^2}$, and their Lie algebras when $A$ is $n \times n$ nilpotent matrix of nilpotency $n$. In this case, we have also proved that the invariants of $Sol_A$ for any $n$, and $Sol_{A^2}$ for $n$ even, are finitely generated.

math.RA↗
arXiv2023

A Complete Characterization of all Magic Constants Arising from Distance Magic Graphs

A positive integer $k$ is called a magic constant if there is a graph $G$ along with a bijective function $f$ from $V(G)$ to first $|V(G)|$ natural numbers such that the weight of the vertex $w(v) = \sum_{uv \in E}f(v) =k$ for all $v \in V$. It is known that all odd positive integers greater equal $3$ and the integer powers of $2$, $2^{t}$, $t \ge 6$ are magic constants. In this paper we characterise all positive integers which are magic constants.

math.CO↗
arXiv2023

Solutions to the matrix Yang-Baxter equation

In this article, we give a few classes of solutions for the Yang-Baxter type matrix equation, $AXA=XAX$. We provide all solutions for the cases when $A$ is equivalent to a Jordan block or has precisely two Jordan blocks. We also have given a few general properties of the solutions of the YB-equation.

math.RA↗
arXiv2020

Approximation of Banzhaf indices and its application to voting games

In this paper, we propose an improved version of the power index related to the Banzhaf power index for weighted voting systems. This index now takes into account the mutual persuasion power matrix(PPM) existing among the voters. This improved index is calculated for European Union voting by basing the PPM on immigration data among the EU countries. We also provide better approximation bounds for the Monte Carlo approximation method for computing power indices.

math.CO↗
arXiv2017

Polynomial Rings Over Commutative Reduced Hopfian Local Rings

In this paper we prove that if $R$ is a commutative, reduced, local ring, then $R$ is Hopfian if and only if the ring $R[x]$ is Hopfian. This answers a question of Varadarajan, in the case when $R$ is a reduced local ring. We provide examples of non-Noetherian Hopfian commutative domains by proving that the finite dimensional domains are Hopfian. Also, we derive some general results related to Hopfian rings.

math.RA↗
arXiv2017

On Hamiltonian cycles of power graphs of abelian groups

In this article we discuss the question of presence of Hamiltonian cycle in the un-directed power graph of a group. In the process we develop weighted Hamiltonian cycle concept and prove a few general results regarding the Hamiltonian question.

math.CO↗
arXiv2014

Beck's Conjecture for Power Graphs

Beck's conjecture on coloring of graphs associated to various algebraic objects has generated considerable interest in the community of discrete mathematics and combinatorics since its inception in the year 1988. The version of this conjecture for power-graphs of finite groups has been addressed and partially settled by previous authors. In this paper we answer it in the affirmative in complete generality, and, in effect, we establish a "nicer" statement on a larger class of graphs. We also clear up certain ambiguities present in the way the previous versions of the conjecture were posed.

math.CO↗
arXiv2014

Hilbert-Samuel Multiplicity of a Bipartite Graph

Let $G$ be a bipartite graph and $I(G)$ the toric ideal associated to the graph $G$. In this article we calculate Hilbert-Samuel multiplicity of the graph $G$ for which the toric ideal $I(G)$ is generated by a quadratic binomials and it satiesfies some conditions.

math.AC↗
arXiv2014

On the number of non-comparable pairs of elements in a distributive lattice

In this article we introduce the study of the number of pairs of non-comparable elements in a distributive lattice $Ł$. We give several tight lower and upper bounds for the number and give as an application the lattices precisely for which the algebraic variety associated to is a complete intersection.

math.CO↗