relation has no temporal argument
## Elucidation
This is used when the first-order logic form of the relation is
binary, and takes no temporal argument.
## Example:
Class: limb
SubClassOf: develops_from some lateral-plate-mesoderm
forall t, t2:
forall x :
instance_of(x,Limb,t)
implies
exists y :
instance_of(y,LPM,t2)
develops_from(x,y)