Elliott carter's technique of using many precisely regulated changes in the speed of the music in order to give it a feeling of fluidity is known as\

Eliott Carter was an American composer, whose personal harmonic and rhythmic language led to the invention of the term metric modulation. The latter describes frequent, precise tempo changes. In David Schiff's book "The Music of Elliott Carter", it is written that Elliott Carter preferred to call it tempo modulation. 

Im not sure but i know it is not b