Functionsumo#list_length_fn(sumo#list -> sumo#nonnegative_integer)returns the number of items in the list, e.g., (sumo#list_length_fn (sumo#list_fn Monday Tuesday Wednesday)) would return the value 3type: pm#unary_function_typeclass of functions requiring a single argument; if R is functional, then if R(x -> y) and P(x -> z) then y=ztype: pm#total_valued_relation_typewhen there exists an assignment for the last argument position of the relation given any assignment of values to every argument position except the last one; note that declaring a relation to be both a total_valued_relation and a single_valued_relation means that it is a total functionsupertype: pm#relation_from_collection (pm#collection,*) supertype: pm#relation_from/to_thing_of_common_kind (*)this type permits to categorize relations according to their signatures and hence offers (i) a concise way to set essential exclusion relations, and (ii) a systematic and easy-to-follow categorizationsupertype: pm#relation__related_thing__relatedthing___related_with (*)type for any relation (unary, binary, ..., *-ary) and instance of pm#relation_typesupertype: pm#what_relation (*) supertype: pm#wh-/how_relation (*)this type permits to categorize relations according to the usual who/what/why/where/when/how questions ; this is a traditional but very subjective and ineffective way of categorizing relationssupertype: pm#relation__related_thing__relatedthing___related_with (*)type for any relation (unary, binary, ..., *-ary) and instance of pm#relation_type