We now want to extend our notion of orthogonality to conditional orthogonality. This will take a bit of work. In particular, we will have to first extend our notions of partition generation and history to be defined on partitions of subsets of .

 

4.1 Generating a Subpartition

Definition 20 (subpartition). A subpartition of a set  is a partition of a subset of . Let  denote the set of all subpartitions of .

Definition 21 (domain). The domain of a subpartition  of , written , is the unique  such that .

Definition 22 (restricted partitions). Given sets  and  and a partition  of , let  denote the partition of  given by .

Definition 23 (generating a subpartition). Given a finite factored set , and