T C C C Beatcs No 109 S C: W M P G S?

The design of efficient algorithms for planar graphs, as a field of research, is over forty year old and continues to be an exciting area. There are several new efficient algorithms for a variety of graph optimization problems that exploit planarity and, in general, the structure of low genus graphs and graphs with excluded minors. Efficient space-bounded computations, on the other hand, involve a different genre of algorithmic ideas and exploit the planar graph structure somewhat differently. There has been a flurry of interesting research on this topic in last decade. In this timely and well-written article, Samir Datta and Raghav Kulka-rni focus on planar graphs in the context of space complexity. They discuss several properties of planar graphs and their precise role in the design of space efficient algorithms.