What is the meaning of "U > F" and "V > U"?

What is the meaning of "U > F" and "V > U"?

U ＞ f is that the object distance is greater than the focal length
It's a standing image
Big is an enlarged image
Virtual is virtual image
V ＞ u is the distance between image and object

What does u F 2F mean in physics
On the lens

Object distance [u]: the distance from the object to the lens
Focal length [F]: the distance from the optical center to the focus
Focal length × 2 [2F]: twice the distance from optical center to focal point
It appears in the third chapter of the first volume of junior high school physics book

What does physics u = f look like

At this time, the incident light becomes a group of parallel rays after refraction, and there is no intersection point, so it cannot be imaged