In the syntactic analysis of the following sentence I doubt:
"They then took the matter to a three-person jury of appeal, specially convened to hear the protest"
The last part in bold (speacially convened to hear the protest) could be 1) an adjunct of reason/cause since it is seprated from the main sentence by a comma. Or on the other hand it could be 2) an appositional relative clause that is post modifying the noun head "jury".
Can you help me? Thanks in advance!
Here is an answer to your question about this:
"They then took the matter to a three-person jury of appeal [that was] specially convened to hear the case."
[I am changing protest to case, but that does not affect the grammar]. The comma would make "that was" irrelevant.
The two criteria for appositives are: they must be right after the noun with which they are identified, and they must have the same grammatical structure.
There are times that an appositive can be out of place (as the one in the link) but in your case, "specially convened to hear the case" describes the three-person jury of appeal, it is not a "renaming"of it.
It is a non-restrictive postmodifier phrase describing the jury of appeal.
I guess some might consider it a relative clause if one wishes to see it as "that was specially convened to hear the case."
