Let there be Wikis A, B then
A is a PartnerWiki to B iff there are pages a in A and b in B, where a is PartnerPage to b.
Corollary: Each Wiki A is a Partner Wiki to A.
Note: As soon as the communities in both Wikis accept one pair of mutual PartnerPages, the process of partnering has made a successful start.
Example: This Wiki. For further examples See TwinPages.