Given an undirected graph, G, and vertices, s and t in G, the tracking paths problem is that of
finding the smallest subset of vertices in G whose intersection with any st path results in a …

The hyperbolicity of a graph, informally, measures how close a graph is (metrically) to a tree.
Hence, it is intuitively similar to treewidth, but the measures are formally incomparable …

Exact learning aims at unambiguously determining an unknown concept from answers to a
carefully crafted set of questions, where each answer, given by an all-knowing oracle …