PlayMakers Repertory Company and PRC artistic director David Hammond relish pushing the edges of the artistic envelope. Rather than endlessly rehashing Shakespeare’s great hits and masterpieces of Modern Drama, this justly renowned regional theater based at the University of North Carolina at Chapel Hill regularly chooses challenging contemporary scripts that, in form or content or language or all three, will shake up the more complacent members of its audience.

One example is Proof, a high invigorating but definitely R-rated comedy of ideas by award-winning American playwright David Auburn. Proof, which debuted on Broadway in 2000, won the 2001 Tony® Award for Best Play and the 2001 Pulitzer Prize for Drama for dramatist David Auburn.

The crusty characters of Proof employ the F-word a lot in exploring the fine line between genius and madness. Auburn focuses his dramatic microscope on a dysfunctional family formerly headed by internationally renowned but mentally ill University of Chicago mathematician named Robert (PRC company member Philip Davidson), now deceased.

In flashbacks and as a ghostly commentator on the action, Davidson brilliantly handles Robert’s mercurial moods. One moment, Robert is lucid and a mathematical genius; the next moment, he starts slipping back, back, back toward the awful abyss of total madness. His quiet, somewhat shy, and sensitive 25-year-old daughter Catherine (guest artist Christina Ross), a gifted mathematician in her own right, postpones completion of her college studies to become her father’s full-time caretaker and confidant, for the last five harrowing years of his life.

The wear and tear on Catherine, body and soul, is something that only a supremely gifted actress, such as Christina Ross, could ever hope to express fully. And Ross is terrific in this role. She is never more luminous than when she is arguing with Robert’s prize pupil, Hal (guest artist and Tectonic Theater Project member Andy Paris).

When he died, Robert left more than 100 notebooks filled with all sorts of scribbling. Could Hal find in them some heretofore unexpected mathematical breakthroughs that Robert conjured during his last lucid moments? Hal is so obsessed with making the next great discovery in his field that at first he barely sees Catherine as a woman, and completely ignores her as a fellow mathematician and a possible peer, with her innate genius compensating for her lack of formal training.

Andy Paris gives a full-blooded, completely three-dimensional characterization as Hal the newly minted Ph.D., a real go-getter who plays in a (lousy) rock band in his spare time. And guest artist Connan Morrissey is excellent as Catherine’s older sister Claire, a control freak who now lives in New York and is never happier than when planning out other people’s lives for them.

All David Auburn’s characters are complicated multilayered individuals, and PRC resident director Ted Shaffner and his cast fully explore all the nuances in this quirky quartet. Scene designer Michael Heil does a nice job of creating the backyard and rear façade of Robert and Catherine’s messy home. Lighting designer Peter West skillfully manipulates his instruments to recreate the ambient outdoor light that illuminates many scenes, costume designer Marion Williams provides just the right casual clothes for the cast, and sound designer/composer M. Anthony Reimer contributes some nice incidental music.

Besides taking home the Tony and the Pulitzer, Proof won a whole shelf load of awards for new playwright David Auburn. The current PlayMakers Repertory Company production of Proof amply demonstrates why. Don’t miss it.

PlayMakers Repertory Company presents Proof Tuesday-Saturday, Dec. 3-7, 10-14, and 17-21, at 8 p.m.; and Sunday, Dec. 8, 15, and 22, at 2 p.m. in the Paul Green Theatre in the Center for Dramatic Art at UNC-Chapel Hill. $9-$34. 919/962-PLAY (7529).