# Irreducibility and Galois Groups of Generalized Laguerre Polynomials $L_{n}^{(-1-n-r)}(x)$

## TL;DR

This paper investigates the algebraic properties of generalized Laguerre polynomials with negative parameters, confirming a conjecture about their irreducibility and Galois groups for many cases and establishing bounds for general cases.

## Contribution

It extends previous work by confirming Hajir's conjecture for all r ≤ 60 and provides a new bound for irreducibility and Galois group containment for larger n.

## Key findings

- Confirmed Hajir's conjecture for r ≤ 60.
- Proved irreducibility and Galois group properties for n > e^{r(1+1.2762/log r)}.
- Extended earlier results of Schur, Sell, Nair, and Shorey.

## Abstract

We study the algebraic properties of Generalized Laguerre polynomials for negative integral values of a given parameter which is $L_{n}^{(-1-n-r)}(x)= \sum\limits_{j=0}^{n} \binom{n-j+r}{n-j} \frac{x^{j}}{j!}$ for integers $r\geq 0, n\geq 1$. For different values of parameter $r$, this family provides polynomials which are of great interest. Hajir conjectured that for integers $r\geq 0$ and $n\geq 1$, $L_{n}^{(-1-n-r)}(x)$ is an irreducible polynomial whose Galois group contains $A_n$, the alternating group on $n$ symbols. Extending earlier results of Schur, Hajir, Sell, Nair and Shorey, we confirm this conjecture for all $r\leq 60$. We also prove that $L_{n}^{(-1-n-r)}(x)$ is an irreducible polynomial whose Galois group contains $A_n$ whenever $n>e^{r\left(1+\frac{1.2762}{{\rm log } r}\right)}$.