clear_symtab()
gentemp()
episode_name()
episode_var()
escaped_symbol_p()
symbolp()
variablep()
dual_var()
duplicate_var()
replaceall()
indent()
standardize()
isquote()
rec_replace()
rec_remove()
listp()
cons()
push()
atom()
append()
flatten()
remove_duplicates()
remove_nil()
subst()
substall()
random_element()
get_keyword_contents()
to_key()
split_by_cond()
extract_category()
rec_find()
rec_find_if()
dict_substall_keys()
cons_dict()
dict_get()
dict_rem_val()
dict_rem()
squash()
normalize()
linsum()
argmax()
certainty_to_period()
has_elapsed_certainty_period()
Given an episode variable like ?e1, return the non-fluent dual of that variable, e.g., !e1 (and vice-versa).