public Set<Literal> getSameStartLiterals(Literal literal, ProvabilityLevel provability) {
		Set<Literal> relatedLiterals = getRelatedLiterals(literal, provability);
		if (null == relatedLiterals) return null;
		Set<Literal> sameStartLiterals = new TreeSet<Literal>();
		Temporal literalTemporal = literal.getTemporal();

		for (Literal l : relatedLiterals) {
			Temporal t = l.getTemporal();
			if (null == t) {
				if (null == literalTemporal || Long.MIN_VALUE == literalTemporal.getStartTime()) sameStartLiterals.add(l);
			} else {
				if (null == literalTemporal) {
					if (Long.MIN_VALUE == t.getStartTime()) sameStartLiterals.add(l);
				} else {
					if (t.sameStart(literalTemporal)) sameStartLiterals.add(l);
				}
			}
		}
		return sameStartLiterals.size() == 0 ? null : sameStartLiterals;
	}