81. Abstracts Of Papers By Carsten Butz A topological completeness theorem. Arch. Math. Logic, 38 (1999), 79101.Abstract We prove a topological completeness theorem for infinitary geometric http://www.itu.dk/people/butz/research/abstracts.html

Carsten Butz Last updated: August 2003. Abstracts of Papers by Carsten Butz Back to Publications Homepage of Carsten Butz Hans-Wolfgang Loidl, Phil Trinder and Carsten Butz Tuning Task Granularity and Data Locality of Data Parallel GpH Programs. Parallel Processing Letters Abstract: The performance of data parallel programs often hinges on two key coordination aspects: the computational costs of the parallel tasks relative to their management overhead - task granularity; and the communication costs induced by the distance between tasks and their data - data locality. In data parallel programs both granularity and locality can be improved by clustering, i.e. arranging for parallel tasks to operate on related sub-collections of data. The GpH parallel functional language automatically manages most coordination aspects, but also allows some high-level control of coordination using evaluation strategies. We study the coordination behavior of two typical data parallel programs, and find that while they can be improved by introducing clustering evaluation strategies, further performance improvements can be achieved by restructuring the program. We introduce a new generic Cluster class that allows clustering to be systematically introduced, and improved by program transformation. In contrast to many other parallel program transformation approaches, we transform realistic programs and report performance results on a 32-processor Beowulf cluster. The cluster class is highly-generic and extensible, amenable to reasoning, and avoids conflating computation and coordination aspects of the program.

82. Computability Complexity Logic Book theorem of Lewis (NEXPTlMEcompleteness of the satisfiability problem of the Corollary NEXPTIME-completeness), theorem of Plaisted and Denenberg http://www.di.unipi.it/~boerger/cclbookcontents.html

Studies in Logic and the Foundations of Mathematics, vol. 128, North-Holland, Amsterdam 1989, pp. XX+592. CONTENTS Graph of dependencies XIV Introduction XV Terminology and prerequisites XVIII Book One ELEMENTARY THEORY OF COMPUTATION 1 Chapter A. THE MATHEMATICAL CONCEPT OF ALGORITHM 2 PART I. CHURCH'S THESIS 2 1. Explication of Concepts. Transition systems, 2 Computation systems, Machines (Syntax and Semantics of Programs), Turing machines. structured (Turing- and register-machine) programs (TO, RO). 2. Equivalence theorem, 26 LOOP-Program Synthesis for primitive recursive functions. 3. Excursus into the semantics of programs. 34 Equivalence of operational and denotational semantics for RM-while programs, fixed-point meaning of programs, proof of the fixed-point theorem. 4*. Extended equivalence theorem. Simulation of 37 other explication concepts: modular machines, 2-register machines, Thue systems, Markov algorithms, ordered vector addition systems (Petri nets), Post calculi (canonical and regular), Wang's non-erasing half-tape machines, word register machines. 5. Church's Thesis 48

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