  We present a new algorithm for subsequence matching in grammar compressed
strings. Given a grammar of size $n$ compressing a string of size $N$ and a
pattern string of size $m$ over an alphabet of size $\sigma$, our algorithm
uses $O(n+\frac{n\sigma}{w})$ space and $O(n+\frac{n\sigma}{w}+m\log N\log
w\cdot occ)$ or $O(n+\frac{n\sigma}{w}\log w+m\log N\cdot occ)$ time. Here $w$
is the word size and $occ$ is the number of occurrences of the pattern. Our
algorithm uses less space than previous algorithms and is also faster for
$occ=o(\frac{n}{\log N})$ occurrences. The algorithm uses a new data structure
that allows us to efficiently find the next occurrence of a given character
after a given position in a compressed string. This data structure in turn is
based on a new data structure for the tree color problem, where the node colors
are packed in bit strings.
