elk-protege/src/main/java/org/semanticweb/elk/protege/proof/InlinedClassInclusionExistentialPropertyExpansionStep.java
static ProofNode<OWLAxiom> canConvertStep(ProofStep<OWLAxiom> step) {
		if (step.getName() != ElkClassInclusionExistentialComposition.NAME) {
			return null;
		}
		List<? extends ProofNode<OWLAxiom>> premises = step.getPremises();
		ProofNode<OWLAxiom> lastPremise = premises.get(premises.size() - 1);
		Collection<? extends ProofStep<OWLAxiom>> lastPremiseSteps = lastPremise
				.getInferences();
		if (lastPremiseSteps.size() != 1) {
			return null;
		}
		// else
		for (ProofStep<OWLAxiom> lastPremiseStep : lastPremiseSteps) {
			if (lastPremiseStep
					.getName() == ElkPropertyInclusionOfTransitiveObjectProperty.NAME) {
				return lastPremiseStep.getPremises().get(0);
			}
		}
		// else
		return null;
	}
static ProofNode<OWLAxiom> canConvertStep(ProofStep<OWLAxiom> step) {
		if (step.getName() != ElkClassInclusionExistentialComposition.NAME) {
			return null;
		}
		List<? extends ProofNode<OWLAxiom>> premises = step.getPremises();
		ProofNode<OWLAxiom> lastPremise = premises.get(premises.size() - 1);
		Collection<? extends ProofStep<OWLAxiom>> lastPremiseSteps = lastPremise
				.getInferences();
		if (lastPremiseSteps.size() != 1) {
			return null;
		}
		// else
		for (ProofStep<OWLAxiom> lastPremiseStep : lastPremiseSteps) {
			if (lastPremiseStep
					.getName() == ElkPropertyInclusionOfTransitiveObjectProperty.NAME) {
				return lastPremiseStep.getPremises().get(0);
			}
		}
		// else
		return null;
	}
Checks if {@link ProofStep} is derived by
{@link ElkClassInclusionExistentialComposition} inference where the last
premise is derived from
{@link ElkPropertyInclusionOfTransitiveObjectProperty}

@param step
@return the transitivity axiom node that is the premise of the inference
for the last premise