rule label
labelan example fact
t`b`
`c`
asf
friend
Jane
Joan
Jack
`y`
Frank
yar
constructor
yar2`c`
`c`
some relation
role_name1role 1
constant a
constant b
role_name2role 2
another relation
constant c
constant d
yac
constant g
constant h
empty
constant h
some relation
role_name1role 1
constant a
constant b
constant b
`b`
role_name2role 2
another relation
constant c
constant d
`x`
role_name3role 3
test
yet another relation
constant b
constant e
constant b
role_name3role 3
`b`