The following few conventions should be noted: item[The identity element] is expected to be in the first class. item[Characters] are lists of cyclotomics (see Chapter Cyclotomics) or unknowns (see chapter Unknowns); they do not physically ``belong'' to a table, so when necessary, functions ``regard'' them as characters of a table which is given as another parameter. item[Conversely], most functions that take a character table as a parameter and work with characters expect these characters as a parameter, too.
      Some functions, however, expect the characters to be stored in the
      irreducibles field of the table (e.g. TestCharTable
      TestCharTable)
      or allow application either to a list of characters given by a
      parameter or to the irreducibles field (e.g. Indicator
      Indicator) if this parameter is missing.
item[The trivial character] need not be the first one in a list of
      characters.
item[Sort convention:]
      Whenever SortClassesCharTable SortClassesCharTable or
      SortCharTable SortCharTable is used to sort the classes of a
      character table, the fusions into that table are not adjusted;
      only the permutation field of the sorted table will be
      actualized.
      If one handles fusions only using GetFusionMap GetFusionMap and
      StoreFusion StoreFusion, the maps are adjusted automatically
      with respect to the value of the field permutation of the
      destination table.  So one should not change this field by hand.
      Fusion maps that are entered explicitly (e.g. because they are not
      stored on a table) are expected to be sorted, they will not be
      adjusted.
GAP 3.4.4