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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 ?
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.
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.
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.
Isabelle Budd's legal expertise and interest in Mark Twain have given us valuable insight as well as information about the Clemens family members and their possessions.
Isabelle tries to satisfy her emotional hunger by bingeing on junk food and then vomiting it up.
Scaliger's discourses are set in a new light by Marie-Dominique Legrand, while Isabelle Pantin and Michel Magnien resurrect the poetic tomb, and Marie-Francoise Piejus judiciously reminds us of the parodic oration.
For example, Isabelle Forest's learning of lithography is based on the author's participation in a workshop where she learned "the different stages of production of a lithograph and [was] allowed .
is exuberantly illustrated by Isabelle Decenciere and comes accompanied by a special audio CD by Drachman.
2002 112 m prod Chaos, At Shepherd Park Productions, exp Carolyn McMaster, Colin Neale, p Carolyn McMaster, d Robert Cuffley, sc Robert Cuffley, Jason Long, ph Mark Dobrescu, ed Ken Berry, pd Paryse Normandeau, c Chris O'Neil, mus Michael Shields; with Katherine Isabelle, Nicholas Campbell, Torri Higginson, Brendan Fletcher, Philip DeWilde, Nikki Barnett.
Isabelle likes to pop the top on this and put on literally everything at one time.
Winnipeg--Jean-Paul Isabelle, superior of the Missionary Oblates of Mary Immaculate (O.
The author depicts the lives of two sisters, Aurore and Isabelle Desjardins, their childhood in the Jura region, their education and sexual development during the fifties and sixties, and their careers and personal experiences until they reach their forties.