(Posted from David Joyner's account but signed by Tony Gaglione) From: "W. David Joyner"Subject: aut gps of free gps 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? Tony Gaglione.