Warren, Robert Bramwell2010-02-102010-02-1020052010-02-10http://hdl.handle.net/1828/2179One method to find the node search number of a graph is to prove identical upper and lower bounds. In four types of grid-like graphs. (h. w)-grids. cylinders. orb webs. and walls, upper bounds are easy to see. However. for tori, the upper bounds are less obvious. requiring two different search strategies. In all cases the lower bounds are not obvious and previously unproven. For these five classes of graphs we develop several techniques for proving lower bounds by taking advantage of the fact that re-contamination does help. We observe that in the five classes of graphs we examine, the node search number can be expressed as a function of the height and width of the graph.enAvailable to the World Wide Webgraph theorycomputable functionsUVic Subject Index::Sciences and Engineering::Applied Sciences::Computer scienceThesis