I want to model negation in Graql rules like below

```
States sub relation is-abstract relates some-resource plays some-state;
stateA sub States relates some-resource;
stateB sub States relates some-resource;
Condition sub relation is-abstract relates some-state;
achieved sub Condition relates some-state;
holds sub Condition relates some-state;
prior sub Condition relates some-state;
$inf isa inference-rule
lhs
{
(some-resource : $a) isa $st;
$st label 'stateA';
(some-state: $st) isa achieved;
# not a valid Graql syntax
(some-state: $st) isnota prior;
}
rhs
{
(some-state: $st) isa holds;
}
```

Which is to say that *if a state is achieved and itâs not a prior state, then it holds*

There can be other combinations as well which might require similar negation in RHS like *if a state is achieved and itâs prior, then it does not hold*

How to model these kind of logic ?