When it comes to proving theories, we tend to think of math or science. But in David Auburn’s drama “Proof,” the heart steps up to validate its own quirky math in which one plus one may not equal two. The heart of this story belongs to Catherine, a 25-year-old college dropout and chief mourner at the funeral of her father, a brilliant but deeply disturbed mathematician at the University of Chicago. The play spins on Catherine’s anxiety about inheriting her father’s tendency toward delusion along with his intelligence.

“Proof,” which won a Pulitzer Prize and a Tony Award in 2001, has been popular on the regional circuit in the last couple of years because it’s a small play – four actors, one set – with big ideas – math, insanity, family, lovers. Next month, a Cantonese version will open at the Hong Kong Arts Center in China. Closer to home, Dead Dogs Productions, an itinerant company that performs in the area in the summer, is presenting “Proof” June 23-25 at Brewer Middle School.

The show opened last Thursday with 10 people in the house. That’s two and a half times the number of people in the cast, and it’s probably just as well, because the actors had not yet found the rhythm of the script. Although the dialogue has a natural cadence, it’s tricky to pull off the nuances of these characters, each of whom has a secret that comes out in the course of the play.

Kae Cooney’s Catherine is so sweetly drawn that her expletives sound girlish rather than venomous, and her most important line of the show, which comes at the end of the second act, tiptoes rather than stomps onto stage. Catherine has suffered emotionally and psychically in her short life. Her unusual life – quitting her own promising education to care for her father as he descends into madness – has forced her toward a maturity that never quite surfaces in Cooney’s portrayal. A little more edge and incredulity would reveal Catherine’s wounds without making her seem whiny. Cooney’s particular talents are at their best when Catherine has a breakthrough of happiness or a flash of hope. It’s the darker side that Cooney struggles to reveal.

Adam Kuykendall as Hal, a former student of Catherine’s father, brings humor to the stage. (He also directed the show.) Rich Kimball, who plays the father in flashbacks and dreams, adds a kind of affable gravitas, which translates effectively into a face-off with his character’s madness. And Pam Rogers, as Catherine’s domineering older sister from New York, plays nearly every scene flatly for anger.

Part of the problem may be that the set, meant to be the back porch of an old house in a Chicago suburb, doesn’t have the organic feel of being lived in. More minimalist than realist, it recedes from the audience, and the actors end up making awkward entrances and exits around lawn chairs and a beer cooler. Set pieces such as a trash can and grill are too far removed to be effective props. Music provided by sound designer Sam Kuykendall gives a jolt of energy to the experience, but additional urban noises – traffic, crickets, birds – are more distracting than subtle.

This is the third time I’ve seen “Proof.” The first was the original Broadway cast, and the second was at a reader’s theater at the University of Maine. Of the three productions, my favorite was the reader’s theater, which, despite its stripped back approach, had an uncanny poetry to it. On opening night, the Brewer production was still calculating the right moves to make this story add up.

Dead Dog Productions will present “Proof” at 8 p.m. June 23-25 at Brewer Middle School, 5 Middle St. For information, call 942-8064. Alicia Anstead can be reached at 990-8266 and aanstead@bangordailynews.net.