def eresolution(clause) -> list:
res = []
for l in range(len(clause)):
lit = clause.getLiteral(l)
if lit.atom[0] == '=' and lit.isNegative():
left = lit.atom[1]
right = lit.atom[2]
unifier = mgu(left, right)
if unifier is not None:
others = []
for ll in range(len(clause)):
lit2 = clause.getLiteral(ll)
if ll != l:
if unifier is None:
others.append(lit2)
else:
others.append(lit2.instantiate(unifier))
new_clause = Clause(others)
new_clause.setDerivation(
flatDerivation("eresolution", [clause, clause]))
res.append(new_clause)
return res
def generateFunCompatAx(f, arity):
"""
Generate axioms for the form
X1!=Y1|...|Xn!=Yn|f(X1,...,Xn)=f(Y1,...Yn)
for f with the given arity.
"""
res = generateEqPremise(arity)
lterm = list([f])
lterm.extend(generateVarList("X", arity))
rterm = list([f])
rterm.extend(generateVarList("Y", arity))
concl = Literal(["=", lterm, rterm], False)
res.append(concl)
resclause = Clause(res)
resclause.setDerivation(Derivation("eq_axiom"))
return resclause
def generatePredCompatAx(p, arity):
"""
Generate axioms for the form
X1!=Y1|...|Xn!=Yn|~p(X1,...,Xn)|p(Y1,...Yn)
for f with the given arity.
"""
res = generateEqPremise(arity)
negp = list([p])
negp.extend(generateVarList("X", arity))
res.append(Literal(negp, True))
posp = list([p])
posp.extend(generateVarList("Y", arity))
res.append(Literal(posp, False))
resclause = Clause(res)
resclause.setDerivation(Derivation("eq_axiom"))
return resclause
