By DONALD LYONS

WHO really is the author of art? What causes a 40-year gap in a man's career? Why are bright, flawed people attracted into the orbit of those who take? These issues dance about in Jon Robin Baitz's new play, "Ten Unknowns," a darkly funny, brilliantly desperate comedy set in Mexico in 1992.

It's directed, with exciting immediacy, by Daniel Sullivan, who also directed, much less urgently, "Proof," in which David Auburn deals with some of the same themes.

But in comparison, Auburn's play is a gimmicky and insubstantial work in which the art of math and the influence of personality are mere plot devices.

"Ten Unknowns" vibrates with vital voices. We're at the hideaway hacienda of once-promising American figurative painter Malcolm Raphelson, portrayed with grace and savoir and anger and seeming certainty by Donald Sutherland.

His white-maned, charming Malcolm became famous in a 1942 article called "Ten Unknowns" and was known for his hatred of Abstract Expressionism, which he paid for (says he) by a long period of tequila-swilling exile and artistic silence. He hasn't shown in 40 years, and his dealer, Trevor, thinks the time is ripe for a retrospective. Plus, Trevor is broke.

Trevor, a nervous, smart type well hit off by Denis O'Hare, is a South African Jew desperately needy for Malcolm to produce a show that includes new stuff. To help Malcolm get the show together, Trevor has been clever enough to send to Mexico one Judd, an ex-boyfriend of Trevor's. He's a feckless, brilliant, druggy young painter and party boy.

Judd has proven a success with Malcolm, who is heterosexual and alcoholic; his helpful presence mixing paints and such has goaded Malcolm to a period of sustained creativity. Malcolm has found a new life; he has produced canvases of Mexico and of his mother that will, in Trevor's opinion, establish his reputation anew when they are seen in Manhattan.

Judd is Justin Kirk, who uses irony, a self-deflating wit, and a weird and wild feel for play to paint a picture of a young man of great gifts but great dependency and neediness.

Kirk's realization of this guy - sharp and brittle and kind - is one of the best of the season. Malcolm spots an attractive Berkeley grad student studying the mating habits of frogs and invites her up to the house. A naif and a nihilist, nicely played by Julianna Margulies, she's a young woman to whom Malcolm is attracted as a painter and as a man. She's more catalyst than character, finally, though.

The production is perfect. Director Sullivan moves his people, trapped in their various doubts, beautifully around Ralph Funicello's expressive set - studio in the rear and a relaxed, open living area up front, with a couch nicely facing upstage.

Sullivan uses the space delicately and deliberately to convey isolation and, occasionally, togetherness. We get a feel that, if these rooms could speak . . . well, see the play.

TEN UNKNOWNS
At the Mitzi E. Newhouse Theater
Lindoln Center.
Through April 15.