RuleML Datalog Fact

(Atom (Ind 'Peter Miller') (op (Rel 'spent at least')) (Ind '5000 euros') (Ind 'in the previous year'))
  <Ind>Peter Miller</Ind>
  <op><Rel>spent at least</Rel></op>
  <Ind>5000 euros</Ind>
  <Ind>in the previous year</Ind>

RuleML Datalog Fact - Notes

This ternary 'spent at least' relationship between the individual Peter Miller, the quantity of currency 5000 euro, and the temporal reference to the previous year can be serialized as a Datalog RuleML fact. Here XML tags -- similar to non-terminals in linguistics -- directly mark up PCDATA (Parsed Character Data) of the surface sentence -- similar to linguistic terminals:

Going through the tags from inside out, we find that "spent at least" is marked up as the relation name (table name) of the fact: <Rel>spent at least</Rel>. On the same level, the three phrases "Peter Miller", "5000 euros", and "in the previous year" are marked up as individual constants that are the three arguments (table columns) of the relation, in the given order: <Ind>Peter Miller</Ind>, <Ind>5000 euros</Ind>, and <Ind>in the previous year</Ind>. The entire relation application constitutes an atomic formula, marked up by <Atom> ... </Atom>.