Philipp Woelfel

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We present a symbolic OBDD algorithm for topological sorting which requires O(log N) OBDD operations. Then we analyze its true runtime for the directed grid graph and show an upper bound of O(log N). This is the first true runtime analysis of a symbolic OBDD algorithm for a fundamental graph problem, and it demonstrates that one can hope that the algorithm(More)
We investigate the remote memory references (RMRs) complexity of deterministic processes that communicate by reading and writing shared memory in asynchronous cache-coherent and distributed shared-memory multiprocessors. We define a class of algorithms that we call <i>order encoding</i>. By applying information-theoretic arguments, we prove that every order(More)
Long-lived renaming allows processes to repeatedly get distinct names from a small name space and release these names. This paper presents two long-lived renaming algorithms in which the name a process gets is bounded above by the number of processes currently occupying a name or performing one of these operations. The first algorithm is asynchronous, uses(More)
We consider augmented ring-based networks with vertices 0,...,n-1, where each vertex is connected to its left and right neighbor and possibly to some further vertices (called long range contacts). The outgoing edges of a vertex v are obtained by choosing a subset D of {1,2,...n-1}, with 1, n-1 in D, at random according to a probability distribution mu on(More)
In this paper, the space requirements for the OBDD representation of certain graph classes, specifically cographs, several types of graphs with few P4s, unit interval graphs, interval graphs and bipartite graphs are investigated. Upper and lower bounds are proven for all these graph classes and it is shown that in most (but not all) cases a representation(More)
We show that for the asymmetric sequential allocation scheme of V&#246;cking (2003) one can use very simple hash functions. The hash functions we use are a straightforward extension of the hash functions introduced by Dietzfelbinger and Woelfel (2003). In order to evaluate a hash function a few arithmetic operations and table lookups suffice. Moreover, we(More)
1Fakultät für Informatik und Automatisierung, Technische Universität Ilmenau, 98684 Ilmenau, Germany (e-mail: 2School of Computer Science, University of Birmingham, Birmingham B15 2TT, UK (email: 3Fakultät für Informatik, Technische Universität Dortmund, 44221 Dortmund, Germany 4Department of(More)