Question: For the Porter stemmer rule group shown in (2.1):
a. What is the purpose of including an identity rule such as SS → SS?
b. Applying just this rule group, what will the following words be stemmed to? circus canaries boss
c. What rule should be added to correctly stem pony?
d. The stemming for ponies and pony might seem strange. Does it have a deleterious effect on retrieval? Why or why not?