I'm surprised that if A is a matrix that there isn't a A.compound_matrix(r) method.
The rth compound matrix can be constructed as
Cr = matrix(A.base_ring(), binomial(A.nrows(), r), binomial(A.ncols(), r), A.minors(r))
Writing a function to do this is trivial. However, it's such an important construction that I'm surprised it's not built-in.
Is it possible that I'm overlooking another method that builds the rth compound matrix?
