  A topos  E  is said to be full if, for any set I, the I-fold copower[3]  ∐I1 of its terminal object exists  in  E.  ∐I1 may be thought of as the canonical representative in  E  of the set I; accordingly, we write it simply as I. (In V(B) this coincides with I as previously defined.) All the toposes mentioned above are full.