[OAI-implementers] resumptionToken in spec

[Alan Kent]

I was just re-reading resumptionToken in the spec I downloaded
a while back and I think the wording of resumptionToken is not
100% clear. (Others have probably said similar things recently.)

When an incomplete list is returned it says use resumptionToken.
It also says "the response containg the incomplete list that completes
the list includes an empty resumptionToken element". No must/should/etc.

Also, what about if the first response is a complete response? Should/must
you return an empty resumption token? Or no resumption token?

The XML Schema says the resumptionToken element is optional in responses
implying it can be omitted sometimes. But it was not 100% clear to me
formally when it can be omitted.

Alan