# A simple backward rule
#
# The numbers five and three are compared using a relation defined by a
# backward rule. When the numeric comparison succeeds, a forward rule
# records the answer.
#
# See <https://www.w3.org/2000/10/swap/doc/tutorial-1.pdf>

@prefix math: <http://www.w3.org/2000/10/swap/math#> .
@prefix log: <http://www.w3.org/2000/10/swap/log#> .
@prefix : <http://example.org/#> .

# something is more interesting if it is greater
{
    ?X :moreInterestingThan ?Y .
} <= {
    ?X math:greaterThan ?Y .
} .

# derivation (forward)
{
    5 :moreInterestingThan 3 .
} => {
    5 :isIndeedMoreInterestingThan 3 .
} .