In Graph systems, the presence of something = true. So, if you have an edge coming out of the entity with alive as the predicate, then that should be sufficient. Provided you set the data right, you could query it like so:
{ me(xid: isaac) { alive }}
If this returns any results, then he’s alive. Otherwise, not.
So, now if you want to find all authors who’re alive and you have edges like:
<author> <instance> <person> .
<person> <alive> "true" .
Then you can find all alive authors like so:
{ me(_xid_: author) { instance { alive }}}
This would give you all authors, and then have the alive bit for all the ones who’re alive.
So, for the database, user and ticket. This is how you could set it up.
<user> <name> "User Name" .
<user> <has> <ticketid0> .
<user> <has> <ticketid1> .
You haven’t mentioned the queries that you want to run. But, this seems like it should give you what you want.