LOWELL — "The machinery is working," the mathematician exultantly tells his daughter in the Merrimack Repertory Theatre's crisp production of "Proof." The character is referring to the creative powers of his mind, but he might as well be referring to David Auburn's Pulitzer Prize-winning drama, which unfolds with the precision of a well-oiled machine.
In a rich and rewarding two hours, Auburn guides us through a jigsaw puzzle that appears to be about the fragility of intellectual brilliance, but is more deeply about the jagged, seemingly unconnected pieces that come together to make relationships, rife with expectations, compromises, risks, and disappointments. "Proof" is also the embodiment of the well-made play, each scene revealing some essential information about the characters, which thrusts the plot forward with mounting urgency.
All of the action takes place on the back porch of a house in Chicago, close to the university and Lake Michigan. Catherine (Keira Keeley), at 25, has sacrificed her college education to care for her father, Robert (Michael Pemberton), a professor and onetime cutting-edge mathematician unable to keep a grip on his sanity.
Robert and Catherine's loving father-daughter relationship is complicated by his illness, but it is also rooted in a shared passion for numbers. Keeley and Pemberton deliver all the affection and concern these two have for each other in the play's warm and gentle opening scene, which culminates in our realization that Catherine is conversing with the ghost of her recently deceased father — a fact that may suggest she's following his spiral into madness. As a devastated Catherine struggles to adjust to her loss, her sister Claire (Megan Byrne), sweeps in from New York to take care of business. Meanwhile, Hal (Colby Chambers), one of her father's former students, arrives to go through Robert's papers in the hope of finding some overlooked mathematical breakthrough.
Director Christian Parker supplies the requisite light touch, anchoring his quartet of actors deeply in their characters. These performers seem utterly comfortable on Lauren Helpern's set, straddling the rock wall of the porch, perching in the deck chairs, pacing in the small yard.
Auburn tells the story out of sequence, so that we move back and forth in time, seeing Robert both sick and well, watching Catherine spar with Hal, then warm to him. Along the way, Keeley offers a Catherine who evolves from numb and wasted — passively allowing Claire to set the course — to tentative and then increasingly willing to leave the safety of her comfort zone. Her winning mix of quirky and funny makes us root for Catherine as she struggles to emerge from her role as caretaker. Auburn's delight in mathematical discovery — which the play's practitioners describe as a lot of hard work, often frustrating, sometimes exhilarating — serves as an apt metaphor for the effort required of a young woman stepping out of her father's shadow and into her own life.