Satre

Congito ergo sum - I think therefore I am.

Satre is a library for proportional and first order logic problem solving in ruby. It was inspired by the book 'Handbook of practical logic and automated reasoning' by Harrison, J (2009).

This project originated at the Technical University Munich as a students project in the lecture 'Basics of Artificial Intelligence'.

Installation

Add this line to your application's Gemfile:

gem 'satre'

And then execute:

$ bundle

Or install it yourself as:

$ gem install satre

Usage

For examples look at the file bin/exercise. The see the results of the exercise run ./bin/exercise from the root directory of this project.

To embed proportional logic solving in your project one can use String#to_formula, on a well formed proportional logic string. Possible operations are

• True value "true"
• False value "false"
• Atomic logical variable "A" (or any other alphanumeric combination)
• logical negation "~A"
• logical and "A /\\ B"
• logical or "A \\/ B"
• Implies "A <=> B"
• If and only if "A ==> B"
• Entails "A |= B"
• Forall "forall x. y"
• Exists "exists x. y"

An example

formula = '(Fire ==> Smoke) /\\ Fire /\\ ~Smoke'.to_formula 

For more examples check bin/exercise_4 and bin/exercise_5 To evaluate a formula use Satre::Formula#eval

formula = '(Fire ==> Smoke) /\\ Fire /\\ ~Smoke'.to_formula 
formula.eval Fire: true, Smoke: true

Further are provided Satre::Formula#tauntolgy?,Satre::Formula#satisfiable?,Satre::Formula#unsatisfiable?, Satre::Formula#holds?,Satre::Formula#wellformed?

For further information see the doc.

Development

After checking out the repo, run bin/setup to install dependencies. Then, run rake to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and tags, and push the .gem file to rubygems.org.

Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/RomanCPodolski/satre. This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the Contributor Covenant code of conduct.

License

The gem is available as open source under the terms of the MIT License.