# lct -- Compute the log-canonical threshold of an arrangement

## Synopsis

• Usage:
lct(A)
• Inputs:
• A, , a central hyperplane arrangement
• Outputs:
• , The log-canonical threshold of A.

## Description

The log-canonical threshold of A defined by a polynomial f is the least number c for which the multiplier ideal J(f^c) is nontrivial.

Let's consider Example 6.3 of Berkesch and Leykin from arXiv:1002.1475v2:

 i1 : R := QQ[x,y,z]; i2 : A := arrangement ((x^2 - y^2)*(x^2 - z^2)*(y^2 - z^2)*z); i3 : lct A 3 o3 = - 7 o3 : QQ
note that A is allowed to be a multiarrangement.