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(theory, tool)
A generic theorem prover with support for several object-logics, developed by Lawrence C. Paulson <> in collaboration with Tobias Nipkow at the Technical University of Munich.

A system of type classes allows polymorphic object-logics with overloading and automatic type inference.

Isabelle supports first-order logic - constructive and classical versions; higher-order logic, similar to Gordon's HOL; Zermelo Fr?nkel set theory; an extensional version of Martin L?f's type theory, the classical first-order sequent calculus, LK; the modal logics T, S4, and S43; and Logic for Computable Functions.

An object logic's syntax and inference rules are specified declaratively allowing single-step proof construction. Proof procedures can be expressed using "tactics" and "tacticals". Isabelle provides control structures for expressing search procedures and generic tools such as simplifiers and classical theorem provers which can be applied to object-logics. Isabelle is built on top of Standard ML and uses its user interface.

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References in classic literature ?
Those who can read German will find an excellent guide, in this respect, in Frau Foerster-Nietzsche's exhaustive and highly interesting biography of her brother: "Das Leben Friedrich Nietzsche's" (published by Naumann); while the works of Deussen, Raoul Richter, and Baroness Isabelle von Unger- Sternberg, will be found to throw useful and necessary light upon many questions which it would be difficult for a sister to touch upon.
I have ruined myself, my friend, ruined myself for the restoration of this young prince who has just passed, cantering on his isabelle colored horse.
Finally, Field's discussion of the piety of both Blanche of Castille and Isabelle herself is very insightful, both in his recognition of the paradoxes both women embodied and in his deft characterization of Isabelle's piety as "a studied simplicity" (128).
Isabelle Costa's parents, Dan and Sophia Costa, just wanted them to come so the parents could say "thank you" for all the support and almost $30,000 in donations.
Isabelle is disturbed by the fact that they have limited her condition by a clinical term that doesn't describe her activity.
Isabelle Fields was on a family trip to Philadelphia last summer when she saw a billboard on Alex's Lemonade Stand.
Speaking on the eve of the second anniversary of the revolutionary op, Isabelle Dinoire, 40, said she wished she could have her old features back.
Twain's Will Be Done," by Isabelle Budd, was included in the Spring 1984 issue of the Mark Twain Journal, followed by a facsimile of Mark Twain's will on pages 34-39.
Isabelle tries to satisfy her emotional hunger by bingeing on junk food and then vomiting it up.
Into this cycle Horn has now introduced Portrait of an Image--Erika, Lena, Claire, Charlotte, Dominique, Jeanne, Mika, Isabelle, Marie, Emma, Beatrice, and Others (with Isabelle Huppert), a work in twenty-two sequences of five photographs--two sequences of which provide Artforum this portfolio--and, with it, a reformulation of the "paradox of the actor.
is exuberantly illustrated by Isabelle Decenciere and comes accompanied by a special audio CD by Drachman.
Projected plans, such as those of the Guises, as described by Isabelle Balsamo, are given as much attention as realized ones in this compilation, and the desires of testators as well as the funeral and festival book and their stunning, emblematic bindings, presented by Georges Frechet, and Isabelle de Conihout Pascal Ract-Madoux are attended to.