Gassmann triple
In mathematics , a Gassmann triple ( or Gassmann-Sunada triple ) is a group "G" together with two faithful actions on sets "X" and "Y" , such that "X" and "Y" are not isomorphic as "G"-sets but every element of "G" has the same number of fixed points on "X" and "Y" . 
<triplet> group <subj> set <obj> has part