(open || closed) world assumption

[elf-pavlik]

• http://en.wikipedia.org/wiki/Open-world_assumption
• http://en.wikipedia.org/wiki/Closed-world_assumption

Paragraph bellow gives me impression of possibly taking closed world assumption. I may interpret it completely different then intended by author, so I would like to clarify which assumption this spec follows.

When serialized, absent properties are represented by either (a) setting the property value to null, or (b) by omitting the property declaration altogether at the option of the publisher; these representations are semantically equivalent. If a property has an array value, the absence of any items in that array must be represented by omitting the property entirely or by setting the value to null.

-- http://jasnell.github.io/w3c-socialwg-activitystreams/activitystreams2.html#syntaxconventions

[jasnell]

Not seeing a specific technical issue here.

[elf-pavlik]

I confused use of JSON null with something in lines of vcard:None

JSON-LD spec also has short paragraph about usage of JSON null, which looks similar to the one here http://www.w3.org/TR/json-ld/#dfn-null