# 1999/4/30
#=============#
# nonexistent #
#=============#
# "nonexistent" is not part of the tabula_rasa hierarchy,
# but it is useful for recording various forms of nonexistents,
# such as imaginary concepts, invalid concepts, and
# anti-concepts.
# The standard Knowledge Explorer output file lists nonexistent,
# followed by the existent hierarchy.
Example: sea serpents