@Override
    public void remove(final String key, final Object value, final T element) {
        final Map<Object, Set<T>> keyMap = this.index.get(key);
        if (null != keyMap) {
            final Set<T> objects = keyMap.get(indexable(value));
            if (null != objects) {
                objects.remove(element);
                if (objects.size() == 0) {
                    keyMap.remove(value);
                }
            }
        }
    }
@author Marko A. Rodriguez (http://markorodriguez.com)
tinkergraph-gremlin/src/main/java/org/apache/tinkerpop/gremlin/tinkergraph/structure/TinkerIndex.java