2017-01-01 14:09:29 -0600 asked a question witt index of quadratic form An important invariant of quadratic forms $(V,q)$ over a field is the Witt index, the dimension of a maximal isotropic subspace of $V$. Is Sage able to calculate this? I have checked http://doc.sagemath.org/html/en/refer... and there does not seem to be anything there to help me (but I may have overlooked it). 2016-11-10 09:33:16 -0600 received badge ● Scholar (source) 2016-11-10 02:54:58 -0600 received badge ● Student (source) 2016-11-10 02:37:22 -0600 asked a question Group of units of number field mod ideal I am wondering whether Sage has a built-in function that takes an ideal $\mathfrak{a}$ of a number field and returns the unit group of the quotient ring $(\mathcal{O}_K / \mathfrak{a})^{\times}.$ More specifically the problem is to iterate through the characters of $(\mathcal{O}_K / \mathfrak{a})^{\times}$ (essentially Hecke characters) and apply them to a given element of $\mathcal{O}_K$. I am at a bit of a loss as to how to do this in Sage.