Halliday & Matthiessen (2014: 476):
With the additive, the Process of a relational dependent clause may be implicit; the marker is the conjunctive preposition with (positive) or without (negative):||| I told the whole story of the six-minute Louvre at The Kennedy Centre || with President Carter there, || and I said, || ‘Mr. President, we have the man [[ who brought the six-minute Louvre back to America]] !’ |||
||| Without chlorine in the antarctic stratosphere, || there would be no ozone hole. |||