[[Rational lattice]]
# Unimodular lattice

A [[rational lattice]] $L$ is **unimodular** iff its [[Gram matrix|Gram determinant]] $\abs{\det G} = 1$. #m/def/geo
An [[Rational lattice#^integral]] unimodular lattice is said to be

- **type I** iff it is odd;
- **type II** iff it is [[Even lattice|even]].


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