This command combines the data in several function tables 
  (objects of class "fv", see fv.object)
  to make a single function table.
  It is essentially a smart wrapper for
  cbind.fv.  A typical application is to calculate the same summary statistic
  (such as the $K$ function) for different point patterns,
  and then to use collapse.fv to combine the results into a
  single object that can easily be plotted. See the Examples.
  
  The arguments ... should be function tables
  (objects of class "fv", see fv.object)
  that are compatible in the sense that they
  have the same values of the function argument. 
  The argument same identifies any columns that are present
  in each function table, and which are known to contain exactly
  the same values in each table. This column or columns will be
  included only once in the result.
  The argument different identifies any columns that are present
  in each function table, and which contain different numerical values
  in each table. Each of these columns will be included, with labels
  to distinguish them. 
  Columns that are not named in same or different will not
  be included.