  An arrangement of hyperplanes is a finite collection of hyperplanes in a real
Euclidean space. To such a collection one associates the characteristic
polynomial that encodes the combinatorics of intersections of the hyperplanes.
Finding the characteristic polynomial of the Shi threshold and the Catalan
threshold arrangements was an open problem in Stanley's list of problems in
[1]. Seunghyun Seo solved both the problems by clever arguments using the
finite field method in [3,4]. However, in his paper, he left open the problem
of computing the characteristic polynomial of a broader class of threshold
arrangements, the so-called "generalized threshold" arrangements whose defining
set of hyperplanes is given by $x_i + x_j = -l,-l+1,...,m-1,m$ for $1 \le i < j
\le n$ where $l,m \in \mathbb{N}$. In this paper, we present a method for
computing the characteristic polynomial of this family of arrangements.
