One of the most well known parallel algorithms for the solution of recurrence equations is the one proposed by Kogge and Stone (it can be found here). They proved that all recurrence equations of the form:
can be solved if the following restrictions are satisfied:
1) $f$ is associative, $f(x,f(y,z))=f(f(x,y),z)$
2) $g$ distributes over $f$, $g(x,f(y,z))=f(g(x,y),g(x,z))$
3) $g$ is semiassociative, that is, there exists some function $h$ such that $g(x,g(y,z))=g(h(x,y),z)$.
Question: Are there any other general algorithms that can solve some class of recurrence equations in parallel?