  The deformation theory of ordinary representations of the absolute Galois
groups of totally real number fields (over a finite field $k$) has been studied
for a long time, starting with the work of Hida, Mazur and Tilouine, and
continued by Wiles and others. Hida has studied the behaviour of these
deformations when one considers the $p$-cyclotomic tower of extensions of the
field. In the limit, one obtains a deformation ring $R_\infty$ classifying the
ordinary deformations of the (Galois group of) the $p$-cyclotomic extension. We
show that if $R_\infty$ is Noetherian and certain adjoint $\mu$-invariants
vanish (as is often expected), then $R_\infty$ is free over the ring of Witt
vectors of $k$.
