FLiP 1.2
F L i P : Logical Framework in Python
Flip is a logical framework written in Python. A logical framework is a library for defining logics and writing applications such as theorem provers. One Flip application is a proof checker for entering and editing proofs in natural deduction style. Here is some output from the checker, generated from a Python proof script:
Kaye ex. 9.12, ~Ax.P(x)  Ex.~P(x) (0) Comment ~Ax.P(x) (1) Given ~Ex.~P(x) (2) Assumption Let x be arbitrary (3) New variable for subproof ~P(x) (4) Assumption Ex.~P(x) (5) EIntroduction (4) F (6) Contradiction (5) (2) ~~P(x) (7) Reductio Ad Absurdum (4) (6) P(x) (8) NotElimination (7) Ax.P(x) (9) AIntroduction (3) (8) F (10) Contradiction (9) (1) ~~Ex.~P(x) (11) Reductio Ad Absurdum (2) (10) Ex.~P(x) (12) NotElimination (11)
The checker can use different logics; Flip comes with several. You can add another logic, or add axioms and derived rules, by writing a module in Python. Python is both the object language and the metalanguage. Formulas, inference rules, and entire proofs are Python expressions. Prover commands are Python functions. The Python interpreter itself is the only user interface to the proof checker application. (It is not necessary to know much Python to use the checker.)
Flip was undertaken as a Python programming exercise. It is not intended to compete with industrialstrength theorem provers such as HOL, nor with nicelydesigned educational provers such as Jape. That said, the checker is quite capable of working the examples and exercises in universitylevel textbooks on logic for computer science or mathematics, such as Kaye, Huth and Ryan, and Bornat.
File  Type  Py Version  Uploaded on  Size  

FLiP1.2.tar.gz (md5)  Source  20110707  91KB  
FLiP1.2.zip (md5)  Source  20110707  140KB  
 Author: Jonathan Jacky
 Home Page: http://staff.washington.edu/jon/flip/www/
 Download URL: http://staff.washington.edu/jon/flip/www/download.html
 Keywords: logical framework python theorem prover proof checker natural deduction
 License: GNU General Public License (GPL)

Categories
 Development Status :: 5  Production/Stable
 Environment :: Console
 Intended Audience :: Education
 Intended Audience :: Science/Research
 License :: OSI Approved :: GNU General Public License (GPL)
 Natural Language :: English
 Operating System :: MacOS :: MacOS X
 Operating System :: Microsoft :: Windows
 Operating System :: OS Independent
 Operating System :: POSIX :: Linux
 Programming Language :: Python :: 2.3
 Topic :: Scientific/Engineering :: Mathematics
 Package Index Owner: jonjacky
 DOAP record: FLiP1.2.xml