Package de.learnlib.oracle

Interface EquivalenceOracle<A,I,D>

Type Parameters:

A - automaton type this equivalence oracle works on

I - input symbol type

D - output domain type

All Known Subinterfaces:

BlackBoxOracle<A,I,D>, BlackBoxOracle.DFABlackBoxOracle<I>, BlackBoxOracle.MealyBlackBoxOracle<I,O>, EquivalenceOracle.DFAEquivalenceOracle<I>, EquivalenceOracle.MealyEquivalenceOracle<I,O>, EquivalenceOracle.MooreEquivalenceOracle<I,O>, InclusionOracle<A,I,D>, InclusionOracle.DFAInclusionOracle<I>, InclusionOracle.MealyInclusionOracle<I,O>, PropertyOracle<I,A,P,D>, PropertyOracle.DFAPropertyOracle<I,P>, PropertyOracle.MealyPropertyOracle<I,O,P>

public interface EquivalenceOracle<A,I,D>

An equivalence oracle, which checks hypothesis automata against the (possibly unknown) system under learning (SUL).

Please note that equivalence oracles are implicitly connected to a SUL, there is no explicit references in terms of a MembershipOracle or such. However, this might be different in implementing classes.

CAVEAT: Equivalence oracles serve as an abstraction to tackle the (generally undecidable) problem of black-box equivalence testing. The contract imposed by this interface is that results returned by the findCounterExample(Object, Collection) method are in fact counterexamples, BUT a null result signalling no counterexample was found does not mean that there can be none.

Nested Class Summary

Nested Classes

Modifier and Type	Interface	Description
static interface	EquivalenceOracle.DFAEquivalenceOracle<I>	A specialization of the EquivalenceOracle interface for a DFA learning scenario.
static interface	EquivalenceOracle.MealyEquivalenceOracle<I,O>	A specialization of the EquivalenceOracle interface for a Mealy learning scenario.
static interface	EquivalenceOracle.MooreEquivalenceOracle<I,O>	A specialization of the EquivalenceOracle interface for a Moore learning scenario.

Method Summary

Modifier and Type	Method	Description
@Nullable DefaultQuery<I,D>	findCounterExample(A hypothesis, Collection<? extends I> inputs)	Searches for a counterexample disproving the subjected hypothesis.

Method Detail

findCounterExample

@Nullable DefaultQuery<I,D> findCounterExample(A hypothesis,
                                                     Collection<? extends I> inputs)

Searches for a counterexample disproving the subjected hypothesis. A counterexample is query which, when performed on the SUL, yields a different output than what was predicted by the hypothesis. If no counterexample could be found (this does not necessarily mean that none exists), null is returned.

Parameters:

hypothesis - the conjecture

inputs - the set of inputs to consider, this should be a subset of the input alphabet of the provided hypothesis

Returns:

a query exposing different behavior, or null if no counterexample could be found. In case a non-null value is returned, the output field in the DefaultQuery contains the SUL output for the respective query.