In my previous question asking about the co-intersection of three circles, a degree six polynomial in twelve variables was found for a special case. This polynomial has precisely 720 terms, of which exactly half are positive and half are negative.
This makes me strongly suspect there is a 6x6 matrix lurking behind the scenes whose determinant is that polynomial. This leads me to the question: How can you tell if an expression is the determinant of a matrix, and if so, how can you find that matrix?
It would be particularly helpful if it could be done for the special case of the polynomial from my previous problem.