The right prescription for people straining to spot changes in New York City Ballet's style is Peter Martins' "Les Petits Riens." This curtain raiser for the third program of the company's current Kennedy Center season, premiered here on Friday, focuses sharply on eight dancers on the ascent. What it shows is that those who care about classicism have nothing to worry about. There are bound to be changes in how repertory staples are performed from season to season, but Martins' school essay is evidence of sound training behind the scenes.

The dancers in "Petits" are anything but clones. Zippora Karz combines grandeur and humor in her facial expressions, in her bearing and in her phrasing as she stalks the stage. Peter Boal's reserve adds excitement to his stretched-leg and bent-knee turns. Wendy Whelan's streamlining crumples neither in supported turns nor in solo jumps; Richard Marsden, her partner, starts moving with a lightning surge. In the air, which seems his element, his red hair turns him into human spark.

A deep stream runs under Jeffrey Edwards' elegant command of technique; he's what Bournonville would have called a dark classicist, and opposite him Margaret Tracey's lightness suggests pairing them in a romantic tragedy. Kelly Cass, short and firm, cuts movement with clarity and musicality. One dancer only, Carlo Merlo, is cast against the grain. He seems to be working classicism out of his system, and one wonders whether a valuable character performer is in the making.

"Petits" shows Martins' growth as a craftsman. It serves the dancers without calling undue attention to itself and has the right sense of play for its Mozart music.

Promises of a new "La Sonnambula" production weren't fully kept. Washington is seeing Alain Vaes' costumes, but his massive set has been damaged; the NYCB has borrowed American Ballet Theatre's scenery.

Friday's powerful performance might just have dispensed with any set. Darci Kistler, as the Sleepwalker, didn't merely skim the Rieti-Bellini melodic line. Her runs on pointe stabbed below the surface. They were exquisite expressions of anger and pain. Leonid Kozlov is the best Baron I've seen in this 42-year-old ballet -- proud but not to the point of overlooking insults, menacing but not inhuman, passionate beyond reason only at the end. Stephanie Saland plays against the brooding Kozlov as if she were Iago in the guise of a Coquette.

Robert LaFosse was the poet intruder into the Baron's castle. Remaking himself as a performer since defecting from American Ballet Theatre, LaFosse has tempered his eagerness, honed his musicality. In this role he was a touch too much the gentleman. Shouldn't the poet be an egotist with self-gratification his foremost concern?

The entertainers at the Baron's party didn't quite convey that they were there to hide an atmosphere of evil, yet the corps of guests seemed totally at home at this odd gathering.

That there has been some shift of style in NYCB dancing could be argued from the concluding piece, s "The Four Temperaments" -- a key work in the Balanchine cannon of classical modernism. As a group the performers were dancing bigger and plusher, even Victor Castelli and Kyra Nichols, though Kipling Houston was showing an incisive new cutting edge and, in the "Choleric" variation, Maria Calegari was sharp as ever.

Adam Lu ders' "Phlegmatic" was hyperrealistic. Lindsay Fischer made his company debut as Nichols' partner. He's medium-tall, fair-haired, lithely built and can exert power. Whether he'll gain neoclassical sharpness while others are letting it go remains to be seen, but in time he'll probably acquire the company's bold, highly raised upper body