For Flute and Bb Clarinet
In English grammar, an infinitive is usually of the form "to ____": "to sketch", "to compose", "to weep". A split infinitive occurs when a word is inserted in the middle of the infinitive: "to boldly go". Written for a very prescriptive theory assignment, "Split Infinitive" recalls the grammatical concept in two ways. Firstly, the form is of necessity ternary (A B A') - the large contrast in mood suggests to me something interrupted and then returned to, yet richer for that interruption - as the insertion of an adverb in the middle of an infinitive. Secondly, each of the three ternary parts splits a collection of pitches between the two voices. In the A section, the (2,3) octatonic collection is used; in the B section, the Bb major collection (not scale!); and in the A' section, the (0,2) octatonic. In the A and A' sections, the split halves are identical in intervallic content: both of prime form (0268) in A and both of prime form (0358) in A'. The B section is split unequally, the flute getting the set (0245) and the clarinet getting the set (0235). Note that the note F is common to both of these halves - and in fact, all three collections. As a result, F becomes a unifying feature throughout the piece and comes to serve as a tonal focus, if not quite a tonal center, particularly in the A' section.
Care should be taken to phrase and articulate as marked, and to keep the B section flowing forwards. The time signature of 4/2 was admittedly chosen to adhere to "number-of-bar" requirements for the theory assignment, but I feel that it encourages a broadness of time that is to be greatly desired - if it does not drag.