A 'mystery dance' from the Alvin Ailey troupe

Although the Alvin Ailey American Dance Theater is a virtual institution in New York, its profile this season is virtually new. About one-third of the 30 dancers are making their debut, and another one- third have been with Ailey only for a year or two.

But just as audiences respond easily and quickly to Ailey's expansive style, so do the dancers themselves. Judging from the opening night of a season that runs until May 25 at the New York City Center, I'd say the company looks like a unit.

They also behaved like thoroughbred professionals in that even if they didn't have an inkling as to what one of the new dances was about, they didn't let on for a minute.

That new dance -- it sure is a puzzler. Kathryn Posin, a guest choreographer , calls it "Later That Day." Though Posin is strictly mainstream, in a show of daring she uses part of a score that Philip Glass composed for Robert Wilson's notoriously avant-garde dance-opera, "Einstein on the Beach." That was the one which went on for six hours at the Metropolitan Opera, and it made momentary celebrities of all, including the audience.

Glass himself has become something of a celebrity via his engrossing music. What keeps the listener glued is the way repetitive cycles of sound modulate into different keys, with occasional droplets of syncopation.

Within the framework of the score's mystique sits Posin's mystery dance. On one side of the stage sit a girl and boy, their nose-thumbling gestures indicating adolescence. Opposite them sits an older man frantically thumbing through the pages of a big book. Stage center is given over to a large chorus, whose repetitive gyrations, extreme and dynamic, imitate the music's chanting. Sometimes it seems as though the Man with the Book, as Dudley Williams is called , is trying to save the youngsters from the lure of the music as represented by the chorus line. Is Posin equating Glass's pleasant mindlessness with his notion of Hades? At other times Williams's utterly colloquial gestures seem a joking putdown. As his troubled expressions become signs of boredom, as his agitated movements slide into impatient twiddlings of the thumb, one wonders if he (and Posin) are not calling the whole Glass cult a bundle of nonsense. And what is that big book anyway? A list of this week's grocery receipts?A conductor's score?

In any case, "Later That Day" ends happily. The chorus line finally snakes off the stage, leaving the boy and girl with each other and the man with his book. At least he's not flipping pages so maniacally anymore.

Ulysses Dove's "Inside," the second premiere of the season, brings the audience back to familiar turf. This solo for Judith Jamison is about love -- fear of it and, finally, acceptance and calm. It allows Jamison a wide range of histrionics, from the trembling and thrashing of the first sections to the almost static presentation of serenity at the end.

Being able to follow the dance's emotional progression doesn't make it interesting, however. Nor can it be convincing when the emotions it expresses are put into such cliched language. But the many fans of Jamison will no doubt appreciate "Inside." It goes on for a long time.