A vigorous looking and talented company, the American Repertory Ballet, now in its 23rd season, has demonstrated anew why it is gaining increased attention during its New York performance at the Joyce Theater (May 6-13). The troupe, an outgrowth of the Princeton Ballet School, performs often in New Jersey, and a sampling of its work, thanks to its run at the Joyce, sends a message that it is worth following the company's future appearances in whatever the venue.A highlight of its opening program was "Lambarena," choreographed by Val Caniparoli, staged by Maiqui Manosa and built upon African dance, with use of music by Johann Sebastian Bach and traditional African songs. In addition to being an impressive piece overall, "Lambaena" was a strong showcase for the skill of striking looking Kymm Clayton, who moves with extraordinary grace and has a commanding presence that augments her talent and makes her a very special attraction for the company. Another coup was the whimsical "Silkscreens," which harked back to the Andy Warhol era and used Peter Bayham's voice-over imitation of Warhol musing on his work and conceptions. The segment was choreographed by Graham Lustig, the company's artistic director. Five dancers with costumes and wigs to help them look like Marilyn Monroe multiplied danced in a sexy recollection of the Warhol connection, and that was followed by a collection of Elvis lookalikes. The opener, "a part between parts," was an explosive study in complex steps and gyrations that creatively showed off what muscular dancers some of the company can be. At the Joyce Theater, 175 Eighth Avenue at 19th Street, $32. Phone 212-242-0800.