Scalar function with more than one variable(Galileon theory)

[NUR JAMAN]

Hi,
Is it possible to define scalar function with more than variable in xAct to work with. Typically In galileon Cosmology,  terms involved  both function of scalar field phi and its kinetic energy. If this can be  done then analytic expression can be achieved. Other wise How To implement Galileon theory in xAct.

Thanks