1. Adjective Clauses - 3 A noun + of which
This pattern carries the meaning of whose: We have an antique table, the top of which has jade inlay --> We have an antique table whose top has jade inlay.
This pattern occurs primarily in formal written English. Commas are used.

2. Adjective Clauses - 3
Reduction of Adjective Clauses to Adjective Phrases
An adjective phrase does not contain a subject and a verb.
Only adjective clauses that have a subject pronoun - who, which, or that - are reduced to adjective phrases

3. Adjective Clauses - 3
The boy (whom) I saw was Tom --> this adjective clause cannot be reduced to an adjective phrase.
The boy who is playing the piano is Ben --> The boy playing the piano is Ben (adjective phrase)

4. Adjective Clauses - 3
1. The subject pronoun is omitted AND the be form of the verb is omitted: The ideas which are presented in that book are interesting --> The ideas presented in that book are interesting.