  Professor M. C. Polivanov and I met only a few times, during my infrequent
visits to the-then Soviet Union in the 1970's and 1980's. His hospitality at
the Moscow Steclov Institute made the trips a pleasure, while the scientific
environment that he provided made them professionally valuable. But it is the
human contact that I remember most vividly and shall now miss after his death.
At a time when issues of conscience were both pressing for attention and
difficult/dangerous to confront, Professor Polivanov made a deep impression
with his quiet but adamant commitment to justice. I can only guess at the
satisfaction he must have felt when his goal of gaining freedom for Yuri Orlov
was attained, and even more so these days when human rights became defensible
in his country; it is regrettable that he cannot now enjoy the future that he
strived to attain.
  One of our joint interests was the Liouville theory,$^{1,\,2}$ which in turn
can be viewed as a model for gravity in two-dimensional space-time. Some recent
developments in this field are here summarized and dedicated to Polivanov's
memory, with the hope that he would have enjoyed knowing about them.
