Wiktionary
n. (context analysis English) A set which is equal to its set of limit points. That is, a set ''A'' is perfect if .
Wikipedia
In mathematics, in the field of topology, a perfect set is a closed set with no isolated points and a perfect space is any topological space with no isolated points. In such spaces, every point can be approximated arbitrarily well by other points: given any point and any topological neighborhood of the point, there is another point within the neighborhood.
The term perfect space is also used, incompatibly, to refer to other properties of a topological space, such as being a G space. Context is required to determine which meaning is intended.
In this article, a space which is not perfect will be referred to as imperfect.
Usage examples of "perfect set".
My shoulder ached where he'd left his mark: a perfect set of his teeth marks set in the flesh of my shoulder.
In return for it, he would give the Treasury a perfect set of printing plates for hundred-dollar bills.
Professor Witherspoon may have made a genuine strike, then the idea occurred to the Navy that here would be the perfect set-up for secrecy.
I was afraid for a second what Id done, but found that other than a perfect set of my own teeth marks, set like a bloody necklace on his skin, I hadnt bitten through to his pulse.
My shoulder ached where hed left his mark: a perfect set of his teeth marks set in the flesh of my shoulder.