sumo#nonnegative_real_number  real_number >= 0
  closed_exclusion:  sumo#negative_real_number
  supertype:  sumo#real_number  a number that can be expressed as a (possibly infinite) decimal, i.e. a number that has a position on the number line
  subtype:  sumo#nonnegative_integer__nonnegativeinteger  integer >= 0
     subtype:  sumo#positive_integer  integer > 0
     subtype:  kif#zero  class containing only 0
  subtype:  sumo#positive_real_number  real_number > 0
     subtype:  sumo#positive_integer  integer > 0

No statement uses or specializes sumo#nonnegative_real_number; click here to add one.