Wolfgang Gehrke

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We present a canonical system for comonads which can be extended to the notion of a computational comonad BG92] where the crucial point is to nd an appropriate representation. These canonical systems are checked with the help of the Larch Prover GG91] exploiting a method by G. Huet Hue90a] to represent typing within an untyped rewriting system. The(More)
This paper shows the expressive power of the functional programming language Standard ML (SML) in the context of computer algebra. It is focused on a special application of the p-adic lifting technique, the Hensel algorithm, that is utilized in a symbolic but also numeric context. This experiment demonstrates that SML provides a suitable frame for the(More)
We present a full proof of a canonical system for adjunctions as already suggested in Cur93]. Termination can be shown in a similar style to HL86]. Connuence is shown by checking all critical pairs. This is done rstly in the Larch Prover GG91] and secondly more correctly in the programming language Elf Pfe89]. Exploiting theorems from category theory BW85](More)
supported by the Italian project MURST ex 40% \Rappresentazione della conoscenza e meccanismi di ragionamento" ABSTRACT We report on an extension of the SML implementation o f t he logic programming l a n guage Elf Pfe94] to support the c heck o f c o n vergence for higher-order critical pairs. Since Elf is based on the Edinburgh Logical Framework HHP93] it(More)
This paper shows how explicit parallel function calls can be deened and implemented on top of Concurrent ML hiding the details about creation and communication of diierent threads. The provided parallel schemes are mainly inspired by the And/Or-parallelism known from logic programming and pipelining which together provide an outline how other schemes can be(More)