Conway symbol (awaiting review)

The Conway genus symbol of an integral lattice $L$ is an invariant of the genus of $L$. It is given in the form $\text{I}_{r,s}(\cdots)$ or $\text{II}_{r,s}(\cdots)$ where the Roman numeral $\text{I}$ or $\text{II}$ indicates the type of $L$, and $(r,s)$ is the signature of $L$.

For a complete description of the Conway symbol, see Conway-Sloane, Chapter 15.