Christoph Kreitz

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The Horus and Ensemble efforts culminated a multi-year Cornell research program in process group communication used for fault-tolerance, security and adaptation. Our intent was to understand the degree to which a single system could offer flexibility and yet maintain high performance, to explore the integration of fault-tolerance with security and real-time(More)
An approach for a simple, general, and unified theory of effectivity on sets with cardinality not greater than that of the continuum is presented. A standard theory of effectivity on F = {f : N 3 N} has been developed in a previous paper. By representations 6: B--* M this theory is extended to other sets M. Topological and recursion theoretical properties(More)
Although building systems from components has attractions, this approach also has problems. Can we be sure that a certain configuration of components is correct? Can it perform as well as a monolithic system? Our paper answers these questions for the Ensemble communication architecture by showing how, with help of the Nuprl formal system, configurations may(More)
R. Gore, A. Leitsch, T. Nipkow, eds. International Joint Conference on Automated Reasoning (IJCAR 2001), LNAI 2083, pp. 421–426, c ©Springer Verlag, 2001. Abstract. JProver is a first-order intuitionistic theorem prover that creates sequent-style proof objects and can serve as a proof engine in interactive proof assistants with expressive constructive(More)
For twenty years the Nuprl (“new pearl”) system has been used to develop software systems and formal theories of computational mathematics. It has also been used to explore and implement computational type theory (CTT) – a formal theory of computation closely related to Martin-Löf’s intuitionistic type theory (ITT) and to the calculus of inductive(More)
The Intuitionistic Logic Theorem Proving (ILTP) library provides a platform for testing and benchmarking automated theorem proving (ATP) systems for intuitionistic propositional and first-order logic. It includes about 2,800 problems in a standardized syntax from 24 problem domains. For each problem an intuitionistic status and difficulty rating were(More)
C. & H. Kirchner, ed. 15 International Conference on Automated Deduction (CADE-15), LNAI 1421, pp. 317–331, c ©Springer Verlag, 1998. Abstract. We present a theorem proving environment for the development of reliable and efficient group communication systems. Our approach makes methods of automated deduction applicable to the implementation of real-world(More)
In previous papers we have presented a unified Type 2 theory of computability and continuity and a theory of representations. In this paper the concepts developed so far are used for the foundation of a new kind of constructive analysis. Different standard representations of the real numbers are compared. It turns out that the crucial differences are of(More)
D. McAllester, ed. 17 International Conference on Automated Deduction, LNAI 1831, pp. 170–176, c ©Springer Verlag, 2000. Abstract. The Nuprl system is a framework for reasoning about mathematics and programming. Over the years its design has been substantially improved to meet the demands of large-scale applications. Nuprl LPE, the newest release, features(More)