Dear Forum members:
Let F be the free group of rank 4 freely generated
by a1,a2,a3,a4. Let w=a1^2*a2^2*a3^2*a4^2.
Proposition 5.7 (due to McCool) of Lyndon and Schupp
asserts that there is an effective procedure for finding
a finite presentation for the stabilizer in Aut(F)
of the cyclic word (w), where (w) is the set of cyclically
reduced conjugates of w. In this particular case, can
anyone tell me what the finite presentation for the
stabilizer is? Or, maybe could you tell me if some software
(for example, GAP) can be used to compute it?