Procedure from library presolve.lib (see presolve_lib).
Usage:
findvars(id ); id=poly/ideal/vector/module/matrix
Return:
list L with 4 entries:
L[1]: ideal of variables occuring in id
L[2]: intvec of variables occuring in id
L[3]: ideal of variables not occuring in id
L[4]: intvec of variables not occuring in id