Similarity on circular data structures

From: Paul F. Dietz (dietz_at_dls.net)
Date: 11/29/03 

Date: Sat, 29 Nov 2003 02:21:59 -0600

Section 3.2.4.2.2 defines the 'similarity' relation on various data
structures. For CONS objects, the definition is:

   Two conses, S and C, are similar if the car[2] of S is similar
   to the car[2] of C, and the cdr[2] of S is similar to the cdr[2] of C.

But consider two cons objects, each of whose car and cdr is itself.
Are these objects similar? The definition does not say.

        Paul