>
> Is the type parameter redundant?
>
Yes, you always have `AbstractArray{T} <: AbstractArray == true`. See the
section
on parametric abstract types in the manual
<http://julia.readthedocs.org/en/latest/manual/types/?highlight=abstract#parametric-abstract-types>.
This also works for (normal) composite types, e.g. `Rational{Int} <:
Rational == true`.Best, Alex.
