[jQuery] traversing with jQuery - complex selector causing brain pain

[jQuery] traversing with jQuery - complex selector causing brain pain


My nav bar consists of a single UL containing LI elements that each
contain a single A.
Well, most of them do.
Some LI elements contain a further UL as well as the A: these
"submenu" UL elements follow the same pattern of containing LI
elements that each contain a single A.
So far, so simple.
Currently, I'm hiding all the submenu UL's on load:
$('#navigation li ul').hide();
But what I want is to only hide the submenu UL's that do NOT contain
an LI containing an A with a class of "selected".
To rephrase: if any of the A elements (which are all inside an LI
element) in that particular subnav UL, have a class of "selected", I
want the UL to remain expanded.
To rephrase even more: I don't want to hide the subnav containing the
current page.
Despite spending far too long examining the "expressions" and
"traversing" documentation, I can't figure out how to build a selector
statement that will encompass them.
Can you help?