ExistentialGraphProofGenerator

Automatedly generates existential graph proofs from a set of premises and a goal provided in propositional logic format. Implements the idea proposed by Bran van Heuveln in his Computability and Logic course at RPI. At the moment, the algorithm only handles valid arguments (does not prove invalidity directly) and has a method of outputting to terminal and an output file. Future work will include handling Pegasus output which is another software developed by an RPI student that visualizes an existential graph proof.

How to run the tool

In terminal and in the project folder, run:

cd src

python generate.py ../testcases/<premise.txt> [-g <goal.txt>] [-o <output-file.pega>]

All premises and goal files should be placed in the testcases folder. If you decide to name your goal file as premise_goal.txt, then you do not need to include the -g flag. Otherwise, include the -g flag and the text file that represents your goal. If you would like to specify an output file, include the -o flag with a file that has the .pega extension.

premises.txt and goal.txt should contain well-formed logic statement (add parentheses around "NOT" and compound statements).

The majority of the terminal output is separated by "phases" in the algorithm from conversion to setup to consistency checking. Intermediary trees will be displayed in a sideways format. From top down, the tree goes from left to right.

Grammar

atoms are '[a-zA-Z]''
not is '~''
and is '&''
or is '|''
implication is '-''
biconditional is '='
contradiction is '!'
left parenthesis is '('
right parenthesis is ')'
and the goal is prepended by '$'

Example

modus_ponens.txt:

  p-q
  p

goal_example.txt: q

Pegasus format

Currently each line in Pegasus starts off with an action and two states: the start and end states. Right now only pseudo-Pegasus output works. That format is outputed to an output file that is either provided through command line or defaults to output.pega.

atoms : A...Z...0...9
cuts: ()
end of atom : |
[-] : stuff in between brackets to be removed
[+] : stuff in between brackets to be added
[/] : keep everything in between these brackets
[.] : notifies where the iteration is coming from

Test Cases

If you go into the testcases, you will see an assortment of potential test files. The folder prop_logic contains problems from Professor van Heuveln's Propositional Logic worksheets. While a lot of the problems do work, the system is still buggy, so please report any problems that should work that do not.

samanthajlee2 / ExistentialGraphProofGenerator