Pythogic
Python package for deal with logical formulas and formal systems.
- Free software: MIT license
- Documentation: https://pythogic.readthedocs.io.
Usage
First of all, create symbols and an alphabet
from pythogic.base.Alphabet import Alphabet
from pythogic.base.Symbol import Symbol
a_sym = Symbol("a")
b_sym = Symbol("b")
c_sym = Symbol("c")
alphabet = Alphabet({a_sym, b_sym, c_sym})
# you can also write:
alphabet = Alphabet.fromStrings({"a", "b", "c"})Create some formulas:
from pythogic.base.Formula import AtomicFormula, TrueFormula, FalseFormula, Not, And, Or
# Propositions
a = AtomicFormula(a_sym)
b = AtomicFormula(b_sym)
c = AtomicFormula(c_sym)
# Elementary formulas
not_a = Not(a)
not_a_and_b = And(Not(a), b)
not_a_or_c = Or(not_a, c)
true = TrueFormula()
false = FalseFormula()Using Propositional Calculus:
from pythogic.pl.PL import PL
from pythogic.pl.semantics.PLInterpretation import PLInterpretation
# A dictionary which assign each symbol to a truth value
symbol2truth = {
a_sym: True,
b_sym: False,
c_sym: True
}
# The propositional interpretation
I = PLInterpretation(alphabet, symbol2truth)
# main class which contains useful methods
PL = PL(alphabet)
PL.truth(a, I) # returns true
PL.truth(b, I) # returns false
PL.truth(c, I) # returns true
PL.truth(not_a, I) # returns false
PL.truth(not_a_and_b, I) # returns false
PL.truth(not_a_or_c, I) # returns true
PL.truth(true, I) # returns true
PL.truth(false, I) # returns falseFeatures
- Compose logical formula by common syntax rules;
- Implementation of several semantics (FOL Interpretation, finite trace, etc.);
- Support for several logical formal systems: Propositional Logic, First-order Logic, REf, LTLf, LDLf;
Credits
This package was created with Cookiecutter and the audreyr/cookiecutter-pypackage project template.
Many thanks to PySimpleAutomata_ for the automata support. .. _PySimpleAutomata: https://github.com/Oneiroe/PySimpleAutomata
