Breadth of a Laurent polynomial ($\mathrm{br}f=\max \mathrm{supp}f-\min \mathrm{supp}f$)

For a nonzero Laurent polynomial, its breadth is the largest exponent with nonzero coefficient minus the smallest such exponent. Unlike its highest exponent, it is unchanged by multiplying by a Laurent monomial unit. The breadth of a nonzero constant is zero.