The Kendall tau distance was originally defined as a correlation coefficient. It seems clear to me that every metric function $d$ that is bounded by $b$, induces a correlation coefficient. That is:
Let $d$ be a metric. Then $-d(x,y)/b+1$ is a correlation coefficient.
I wonder if the converse is true, too:
Let $c(x,y)$ be a correlation coefficient. Then $-c(x,y) + 1$ is a pseudometric.
Is the latter statement true or false?