We study the parallel complexity of computing the arboricity of a graph, defined as the minimum number of forests into which its edges can be partitioned.
For graphs of bounded treewidth, we present a simple dynamic programming–based parallel algorithm that constructs an optimal partition of the edges into forests.
For ... more >>>

The problem of recognizing $(k,l)$-tight graphs is a fundamental problem that has close connections to well studied problems
like graph rigidity. The problem is better understood for planar graphs as compared to general graphs. For example, deterministic
NC-algorithms for the problem are known for planar graphs, but no such ... more >>>

We present an algorithm for constructing a depth-first search tree in planar digraphs; the algorithm can be implemented in the complexity class UL, which is contained in nondeterministic logspace NL, which in turn lies in NC^2. Prior to this (for more than a quarter-century), the fastest uniform deterministic parallel algorithm ... more >>>

We provide new upper bounds on the complexity of the s-t-connectivity problem in planar graphs, thereby providing additional evidence that this problem is not complete for NL. This also yields a new upper bound on the complexity of computing edit distance. Building on these techniques, we provide new upper bounds ... more >>>