Lefrançois and Gandon, 2013b) proved that in the hierarchy of unit types, if t ∩ 1 ∩ t ∩ 2 then the actantial structure of t ∩ 1 is more specific than that of t ∩ 2 , except for some degenerated cases.
as one goes down the hierarchy of unit types, an ASlot with symbol s is introduced by the radix {γ γ γ(s)} and first defines an optional ASlot for any unit type t ∩ more specific than {γ γ γ(s)}, as long as t ∩ is not more specific than the obligat {γ γ γ 1 (s)} (resp.