Simple utility returning names of variables involved in a kernel semi parametric model.
# S3 method for kspm
variable.names(object, ...)an object of class "kspm", usually, a result of a call to kspm.
additional optional argument (currently unused).
a list of character vectors. The first element correspond to the names of variables included in the linear part of the model. Then, a vector containing names of variables including in kernel part is provided for each kernel.