Implications of removing $has$a

Hi,

I tried removing $has$a from XDI4j (http://wiki.eclipse.org/XDI4j) to see what it breaks.
Actually I found only one piece: Versioning

In XDI Versioning we were using $has for "version snapshots" and $has$a for "version logs".

- A "version snapshot" is a complete copy of a subject at a given version
- A "version log" is a copy of the XDI message that produced the given version

We had a nice wiki page about this, but somehow I can't find it right now.

Anyway, here is an example XDI document with 2 versions of =markus, complete with "version snapshots" and "version logs":

=markus
    +name
        "Markus Sabadello"
    $has

        $v
    $v
        !2
    +friend
        =drummond
=markus$v
    $has
        !2
    =markus$v!1
        /
            =markus
                $add
                    /
                        =markus

                            +name
                                "Markus Sabadello"
    $has$a
        =markus$v!2
    =markus$v!2
        /
            =markus
                $add
                    /

                        =markus
                            +friend
                                =drummond
=markus$v!1
    +name
        "Markus Sabadello"
=markus$v!2
    +name
        "Markus Sabadello"

    +friend
        =drummond

My guess is that we can simply leave out the one $has$a statement, since it doesn't really add much additional information anyway. But maybe someone has a better idea...

Markus