I've been playing around with the sympy vector module and the expressions created in latex contain very large subscripts denoting their reference system. Please see the attachment if the graphic does not appear below.

I have x and y defined as symbols and C as the reference system. The inclusion of the subscript C for every term is not necessary for my application and quickly gets very ugly for larger expressions with many variables.
I want to get rid of these subscripts. They are discouraging me from working with the vector module. How can I disable them please?