#> Why would its values be more representative of a function than the
#> relationship that gives rise to it?
#
#"Is mother of," {le ka/du'u ce'u mamta ce'u}, is a relation and, indeed, a
#function, as a set of ordered pairs --though the order is reversed here, so
#{le du'u ce'u se mamta ce'u} . There are many functions for which it is
#somewhat unnatural to think of the corresponding relation (sum, product, and
#the like, for example) and, indeed, the relations can usually be expressed
#only by an equation between the function with an argument and its value for
#that argument (though one way of doing Logic does take this notion as basic,
#to simplify some kinds of metatheoretical proofs).
I think it would be very helpful to use Sum rather than Mamta as an example.