We make progress in understanding the complexity of the graph reachability problem in the
context of unambiguous logarithmic space computation; a restricted form of nondeterminism …

We study the complexity of restricted versions of st-connectivity, which is the standard
complete problem for NL. In particular, we focus on different classes of planar graphs, of …

We present a deterministic Logspace procedure, which, given a bipartite planar graph on n
vertices, assigns O (log n) bits long weights to its edges so that the minimum weight perfect …

Reachability and shortest path problems are NL-complete for general graphs. They are
known to be in L for graphs of tree-width 2 (Jakoby and Tantau in Proceedings of …

Viewing the computation of the determinant and the permanent of integer matrices as
combinatorial problems on associated graphs, we explore the restrictiveness of planarity on …

Designing algorithms that use logarithmic space for graph reachability problems is
fundamental to complexity theory. It is well known that for general directed graphs this …

Attention, ce résumé comporte un peu d'ironie et d'humour. Dans ce mémoire, nous
défendons l'idée selon laquelle, pour tout modèle de calcul raisonnable, ce n'est plus tant le …

The purpose of this article is to survey several useful properties of planar graphs that can be
exploited specifically in the context of space bounded computation to obtain efficient …

For a graph G (V, E) and a vertex s∈ V, a weighting scheme (w: E→ N) is called a min-
unique weighting scheme, if for any vertex v of the graph G, there is a unique path of …

A primary research goal in the study of expander graphs is the construction of explicit
expander graph families. Namely, we want to construct a family of graphs {Gn} n∈ N, where …