elk-reasoner/src/main/java/org/semanticweb/elk/reasoner/indexing/classes/IndexedObjectPrinter.java
@Override
	public String visit(IndexedClass element) {
		ElkClass entity = element.getElkEntity();
		if (entity.getIri().equals(PredefinedElkIris.OWL_THING)) {
			return "⊤";
		}
		// else
		if (entity.getIri().equals(PredefinedElkIris.OWL_NOTHING)) {
			return "⊥";
		}
		// else
		return entity.toString();
	}
@Override
	public String visit(IndexedClass element) {
		ElkClass entity = element.getElkEntity();
		if (entity.getIri().equals(PredefinedElkIris.OWL_THING)) {
			return "⊤";
		}
		// else
		if (entity.getIri().equals(PredefinedElkIris.OWL_NOTHING)) {
			return "⊥";
		}
		// else
		return entity.toString();
	}
TODO: parentheses and precedence of symbols