You can do backward traversal, using "^" instead of "." as punctuation.
For example, if we know Dan's mailbox...
:dan con:mailbox <mailto:connolly@w3.org>
then we can write this expression for Dan:
<mailto:connolly@w3.org>^con:mailbox
Note: This is rather unlike javascript, python, and
other object-oriented programming langauges