M. Jünger, S. Leipert, M. Percan, Technical Report No. 2002.435 (2002). Abstract A clustered graph C=(G,T) consists of an undirected graph G and a rooted tree T in which the leaves of T correspond to the vertices of G=(V,E) . Each vertex mu in T corresponds to a subset of the vertices of the graph […]
M. Jünger, S. Leipert, P. Mutzel Technical Report No. 99.369, Universität zu Köln, Germany (1999) Abstract A level graph G = (V,E,lev) is a directed acyclic graph with a mapping lev : V -> {1,2,…,k}, k >= 1, that partitions the vertex set V as V = V1 u V u…u Vk, V = lev […]
S. Leipert Technical Report No. 97.259, Universität zu Köln, Germany. (1997) Abstract PQ-trees are a data structure being used to represent the permutations of a set U in which various subsets of U occur consecutively. Along with the data structure, efficient algorithms for manipulating PQ-trees are given, requiring linear time in the size of the […]
S. Leipert PhD-Thesis, Institut für Informatik, Universität zu Köln, Germany (1998)
S. Leipert Technical Report No. 96.242, Universität zu Köln, Germany. (1996) Abstract The Tree Interface is a graphical tool specially designed to draw binary and general rooted trees, as they occur during an algorithmic process. It can be used in three different contexts. Simple drawing of trees. As a result of an algorithmic process, a […]
M. Jünger, S. Leipert, P. Mutzel Technical Report No. 96.227, Universität zu Köln, Germany. (1996) Abstract The problem of computing a maximal planar subgraph of a non-planar graph has been deeply investigated over the last 20 years. Several attempts have been tried to solve the problem with the help of PQ-trees. The latest attempt has […]