elk-reasoner/src/main/java/org/semanticweb/elk/reasoner/Reasoner.java
public synchronized boolean isSatisfiable(
			ElkClassExpression classExpression) throws ElkException {

		if (classExpression instanceof ElkClass) {
			final TaxonomyNode<ElkClass> queryNode = getTaxonomyNode(
					(ElkClass) classExpression);
			return !queryNode.contains(getElkFactory().getOwlNothing());
		}

		return querySatisfiability(classExpression);
	}
public synchronized boolean isSatisfiable(
			ElkClassExpression classExpression) throws ElkException {

		if (classExpression instanceof ElkClass) {
			final TaxonomyNode<ElkClass> queryNode = getTaxonomyNode(
					(ElkClass) classExpression);
			return !queryNode.contains(getElkFactory().getOwlNothing());
		}

		return querySatisfiability(classExpression);
	}
Check if the given {@link ElkClassExpression} is satisfiable, that is, if
it can possibly have instances. {@link ElkClassExpression}s are not
satisfiable if they are equivalent to {@code owl:Nothing}. A satisfiable
{@link ElkClassExpression} is also called consistent or coherent. Calling
of this method may trigger the computation of the taxonomy, if it has not
been done yet.

@param classExpression
the {@link ElkClassExpression} for which to check
satisfiability
@return {@code true} if the given input is satisfiable
@throws ElkException
if the result cannot be computed