Problem 155
(Thurston-Sullivan?) Are all smooth actions of $\Phi _g$ on $\mathbb S^1$ which are topologically conjugate to a standard one differentiably conjugate to the standard one?

(Thurston-Sullivan?) Are all smooth actions of $\Phi _g$ on $\mathbb S^1$ which are topologically conjugate to a standard one differentiably conjugate to the standard one?

Comments
Yes. [shub1985expanding]
assuming we are talking about nielsens action of the mapping class group on the circle at infinity…the only question that I recall makes sense is to show this [ continuous even quasisymmetric ] action is not conjugate to a smooth action [even C1 or even absolutely continuous] because the absolute continuity is the obstruction to mostow rigidity in this dimension [ absolute continuity holding for quasiconformal or quasi symmetric in higher dim.yielding mostow rigidity]