Skip to main content

All Questions

Filter by
Sorted by
Tagged with
5 votes
3 answers
1k views

On the automorphism group of binary quadratic forms

This question is a continuation of the following two questions: Discriminants of indefinite integral binary quadratic forms admitting 3 or 6 torsion. On certain solutions of a quadratic form ...
Stanley Yao Xiao's user avatar
6 votes
2 answers
463 views

On certain solutions of a quadratic form equation

This is a continuation of this question: A class of quadratic equations Let $f(x,y) = ax^2 + bxy + cy^2$ be an irreducible and indefinite binary quadratic form. Consider the equation $$\displaystyle ...
Stanley Yao Xiao's user avatar
5 votes
1 answer
205 views

Stabilizers of pairs of ternary quadratic forms

Let $A,B$ be two ternary quadratic forms with real coefficients, given by symmetric matrices $$\displaystyle 2A = \begin{pmatrix} 2a_{11} & a_{12} & a_{13} \\ a_{12} & 2a_{22} & a_{23}...
Stanley Yao Xiao's user avatar