The free-theorems-counterexamples package

[Tags: library, program, public-domain]

This program is to verify (or to put into question) strictness conditions on free theorems that arise if a polymorphic lambda calculus is enriched by general recursion. Given a type the program either returns an instance of the corresponding unrestricted free theorem that does not hold and thereby verifies the need of the additional restrictions or it returns without finding such an instantiation and thereby suggests (but not proves) that the strictness conditions are superfluous. The underlying algorithm is described in "Automatically Generating Counterexamples to Naive Free Theorems" (FLOPS'10) by Daniel Seidel and Janis Voigtländer. A webinterface for the program is also available at

Related to this package you may be interested in the online free theorem generator at that is also available offline via Also interesting may be the tool polyseq that generates "optimal" free theorems in a polymorphic lambda calculus with selective strictness. Polyseq can be downloaded at but the functionality is as well provided via a webinterface at

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Change logNone available
Dependenciesbase (>=1), cgi, containers (>=, free-theorems (>=, haskell-src (>=1.0), haskell-src-exts (>=0.3.9), HUnit (>=1.2), mtl (>=1.0), pretty (>=, syb (>=, utf8-string, xhtml [details]
AuthorDaniel Seidel, Joachim Breitner
UploadedThu Feb 14 13:36:17 UTC 2013 by DanielSeidel
Downloads688 total (16 in last 30 days)
0 []
StatusDocs not available [build log]
Successful builds reported [all 6 reports]



Maintainers' corner

For package maintainers and hackage trustees

Readme for free-theorems-counterexamples-

The module free-theorems-counterexamples-0.3 can be installed the following way:

runhaskell Setup.hs configure --user
runhaskell Setup.hs build
runhaskell Setup.hs haddock
runhaskell Setup.hs install

runhaskell Setup.hs haddock builds the documentation.
This step is not necessary.

After installation the modules
are available.

To start the webinterface do

$ ./

then it runs under  http://localhost:8002/

The webinterface can also be found under