Integral quadratic lattice
= Integral quadratic lattice
{title2=$L\cong\mathbb Z^n,\quad B:L\times L\to\mathbb Z$}
An integral quadratic lattice is a finite-rank <free abelian group> with a nondegenerate integral symmetric <bilinear form>. Its norm convention here is $q(x)=B(x,x)$. A basis gives an integral <Gram matrix>; basis changes preserve its determinant up to multiplication by the square of a unit.