William Forsythe and James Kudelka, although not yet household names, are certainly the most original choreographers to emerge from the ballet world since 1980. It doesn't seem like limb-climbing to venture that they will also prove to be among the very best. Each has just created a superb world premiere for the San Francisco Ballet.
Mr. Forsythe's premiere, ''New Sleep,'' was a special risk. Like Mr. Kudelka, he has shown two works in the Joffrey Ballet. This is, however, a choreographer with increasingly radical ideas. In ''New Sleep,'' the cerebral structures underlying the choreography's fast and intricate step combinations, the constant light play with varying shades of darkness and the percussive electronic score might have put off an audience accustomed to a more conventional view of ballet.
Nonetheless, at Friday's premiere in the San Francisco War Memorial Opera House, the resounding cheers - continuing after the house lights went on - came from an exuberant public obviously stimulated by Mr. Forsythe's shrewd sense of theatrics.
''New Sleep'' continues Mr. Forsythe's investigation into the formal elements that go into ballet dancing. But as far as the audience is concerned, his compositional structures are less important than the sense of adventure he creates so effectively on stage. ''New Sleep'' is a suspense story, full of non sequiturs that never add up to a logical whole and yet compulsively hold a viewer's attention.
The action is so rapidly paced that there is no time to worry about the relationship between an ensemble of 12 dancers dressed in shining black tops and tights and a mysterious black-clad trio that mimes more than it dances. This trio consists of Victoria Morgan, looking schoolmarmish in a big pleated skirt and holding a prop ruler, Christopher Anderson in a dunce cap and David Kern in a mortarboard.
In a typically sly aside in a program note, Mr. Forsythe calls the trio ''a family engaged in research in the applied sciences.'' The various Dada-like activities of the ''family'' are concurrent with the explosive energy of the ensemble. This group speaks a very different dance language - the women engaged in fast and furious toe work and the men with loose torsos and just as furiously engaged in the swiveling contours and off-balanced look Mr. Forsythe gives to the standard ballet silhouette.
Mr. Forsythe's central concern here seems to be the interaction between order and disorder. The measuring-rod mentality of the ''family'' is contrasted with the freedom he gives the dancers within classical ballet's rules. The dancers are supposedly allowed a certain autonomy, Merce Cunningham-style, within the movement material the choreography gives them.
The important thing to remember is that Mr. Forsythe is a classical-ballet choreographer, not a modern-dance choreographer, and his command of the academic lexicon is striking. So in the end it is the amazing movement combinations of ''New Sleep'' and the way it is presented that makes the ballet so eye-riveting.
Mr. Forsythe has created complex computerized lighting (at a cost of $30,000 underwritten by two patrons, Mr. and Mrs. Thomas J. Perkins). Frequently the ballet recalls Ad Reinhardt's paintings - black on black. In the finale and a few selected other moments, the near obscurity of the dancers - only torsos visible in a glow - is magical rather than irritating. Tom Willems, a Dutch composer, has created a compelling electronic score that contributes to the futuristic environment.