Presenting the subject of a fugue in shortened time values is called

Presenting the subject of a fugue in shortened time values is called Diminution.

Explanation:

In Western music and music hypothesis, reduction has four unmistakable implications. Reduction might be a type of adornment wherein a long note is partitioned into a progression of shorter, generally melodic, values.

Diminution is likewise the term for the corresponding shortening of the estimation of individual note-shapes in mensural documentation, either by hue or by an indication of extent.

A minor or flawless interim that is limited by a chromatic semitone is a lessened interim, and the procedure might be alluded to as decrease.