private Number getRangeBound(OperatorNode<ExpressionOperator> bound) {
        if (bound.getOperator() == ExpressionOperator.NEGATE)
            return negate(getPositiveRangeBound(bound.getArgument(0)));
        else
            return getPositiveRangeBound(bound);
    }
Build a "pure" not, without any positive terms.
container-search/src/main/java/com/yahoo/search/yql/YqlParser.java