Halliday &
Matthiessen (2014: 490):
There is one type of non-finite dependent clause which is often not recognised because it has no verb in it; for example, with no-one in charge, with everyone so short of money. These are in fact ‘attributive relational’ clauses, with zero alternation of the non-finite verb being (less commonly they may be identifying, eg with that the only solution). The verb be will always be present in the agnate finite clause (eg since no-one is in charge); and in the non-finite it is always possible to insert being, with very little difference in meaning.