Skip to content
A theorem prover using G4ip
Branch: master
Clone or download
Fetching latest commit…
Cannot retrieve the latest commit at this time.
Type Name Latest commit message Commit time
Failed to load latest commit information.


Implementation of a theorem prover for propositional logic using G4ip in Haskell.

File Structure

  • G4ip/Proposition.hs -- Definition of propositions and some syntactic sugar
  • G4ip/Decider.hs -- The actual theorem prover (decider?)
  • G4ip/Tester.hs -- For defining and running tests
  • G4ip/TestMain.hs -- Actually runs the default test suite

Testing Manually

  • Startup ghci
  • Load Main.hs by typing :l Main
  • Use decide prop to see if prop is provable.

You can use T, F, /\, \/, ==>, <==, <=>, neg, and () with their usual meanings to form propositions. To form an atom, either use Atom "name" or use one of the predefined atoms: a, b, c, d, e, or f. Here is an example:

decide $ (neg b ==> neg a) ==> (a ==> b) \/ (a \/ a ==> a)

which prints True as expected ($ if for associativity, you can use parenthesis if you want).


Email me at for any questions.

You can’t perform that action at this time.