This is a good point—I am now regretting not having given more technical details on what it means to be “order preserving”.
The requirement is that X > 0 ==> X + Y > Y. I’ve generated the graph under the assumption that Medium > 0, which results in (very good, medium) > (very good). Clearly the antecedent doesn’t hold if Medium < 0, in which case the graph would go the other direction, as you point out.
This is a good point—I am now regretting not having given more technical details on what it means to be “order preserving”.
The requirement is that
X > 0 ==> X + Y > Y. I’ve generated the graph under the assumption thatMedium > 0, which results in (very good, medium) > (very good). Clearly the antecedent doesn’t hold ifMedium < 0, in which case the graph would go the other direction, as you point out.