New York, New York

We recently fled L.A.’s globally warmed climes to take in some of New York‘s fall theater season, and found the big town as reassuringly cold and anti--Los Angeles as ever. Whatever your opinion of the two cities, a week in Gotham will provide a veritable festival of quality theater work -- a festival that is virtually permanent, as long-running hits are constantly replaced by new shows and by short-run works appearing off-off-Broadway and at performance spaces like P.S. 122 and HERE. At heart, New Yorkers remain closet romantics: The most telling spectacle we witnessed took place in Chelsea one afternoon, when a double rainbow formed over the Empire State Building, emptying bars and cafes of people who oohed and aahed into their cell phones as they described the sight to friends -- even The New York Times felt compelled to report the event. Below are what we saw onstage one week; unless otherwise noted, call (212) 239-6200 for tickets and information.

COPENHAGEN Michael Frayn’s moral drama speculates on what a meeting between physicists Werner Heisenberg and Niels Bohr, and Bohr‘s wife, Margrethe, would be like. Such a gathering, occurring after World War II, would have more than passing interest to historians: Heisenberg (Michael Cumpsty), who had formulated the principle positing that the mere observation of an event changes that event, however subtly, was one of Hitler’s chief A-bomb-program planners; the Danish Bohr (Philip Bosco) was his mentor and a half-Jew who fled ahead of the Nazis to America and Los Alamos. In Frayn‘s initially frosty reunion, the two are really obsessed with re-enacting an earlier tete-a-tete that took place during the war when Heisenberg, then deliberately trying to throw the German bomb program off track, went to Niels and Margrethe (Blair Brown) in Denmark to satisfy his own curiosity as to whether or not the Allies were working on a nuclear device to annihilate Germany. Just what did the two estranged friends reveal to one another, and how did it affect their behavior during the war? This is a must-see evening that combines the best in theater: a seemingly unsolvable mystery, an intractable moral dilemma, and a cast that completely inhabits the playwright’s characters and themes. Royale Theater, 242 W. 45th St.

PROOF David Auburn‘s drama about the troubled daughter of a brilliant but demented mathematician has generated enormous buzz here. It’s easy to see why critics and public alike have fallen for actor Mary-Louise Parker: Her performance as the mercurial Catherine, who converses with her departed father (played by Larry Bryggman) and who herself may or may not have worked out an important new math proof, is a bewitching display of rage and awkward vulnerability. And, in director Daniel Sullivan‘s steady hands, the rest of the cast, even though composed of single-note portrayals, runs with those repetitive characterizations for all they are worth: Would-be boyfriend Hal (Ben Shenkman) and sister Claire (Johanna Day) are both endearing and vexing as they demand evidence of Catherine’s authorship of an innovative arabesque of figures. But by Act 2, it‘s clear that those steady hands of Sullivan are less busy steering a fully realized work than they are playing a shell game with a script that is, at best, only three-quarters complete. Parker’s portrayal confers upon Auburn‘s anemic second act an unwarranted emotional grandeur and, ultimately, more importance than his play deserves. Walter Kerr Theater, 219 W. 48th St.

TABLETOP There’s something delightfully formulaic about the characters and situations in Rob Ackerman‘s satire about a bickering crew of filmmakers. Here is a young, arty rebel whose ideas are routinely dismissed as uncommercial; there are the technicians -- one a closeted gay, the other a get-along black -- who try to play the degrading industry game without making waves; the A.D. who rides herd and busts balls to compensate for being the sole woman onboard; and finally, the aging director who faces professional extinction if he can’t bring this shoot in on time. What gives such stereotypes their brio is the story‘s milieu: Our crew doesn’t make Hollywood movies but TV commercials -- and not even the whole ads, only the product inserts that highlight those 30-second spots known in the trade as ”tabletops.“ Ackerman, a career property master in this business, knows his territory all too well, and from the opening moment we are drawn into a claustrophobic, esoteric world of lighting and camera equipment, and the technical Esperanto with which his characters communicate. Ackerman‘s play, which closed at the American Place Theater this week, is a fascinating study, uncompromising in its bleak comedy and, it would seem, a natural export to Los Angeles.

JESUS HOPPED THE A TRAIN Here’s one difference between L.A. and N.Y.: In our theater-program bios almost every actor seems to have been on ER, a while in New York Law and Order is the great TV showcase and rent payer. Stephen Adly Guirgis‘ grim prison drama about two men living in a protective-custody wing on Riker’s Island boasts three such L&O alumni, including Guirgis, whose unrelenting story may be considered a nightmare spinoff of that TV show. Even the lighting seems brutal, so it‘s not surprising Jesus Hopped the A Train’s somber story is told in a language both sinewy and harshly poetic. Guirgis stumbles somewhat by having his attorney character (Elizabeth Canavan) ”clarify“ plot points through direct address to the audience, but this show, effortlessly guided by director Philip Seymour Hoffman, belongs to John Ortiz, who plays a man accused of shooting a cultish preacher, and to Ron Cephas Jones as a born-again Christianserial killer. Their moments of quarreling or comforting each other within their respective holding cells are never less than electric -- a chemistry whose catalyst is often their sadistic guard, played to a fine point by David Zayas. Guirgis is clearly a playwright to watch; this LAByrinth Theater Company production has just closed at the East 13th Street Theater, but there has been talk of its opening at another venue this spring.