Proof ★★★★

Early in the Broadway revival of David Auburn’s Tony- and Pulitzer-winning Proof, sudden small flashes of red light started appearing behind stars Don Cheadle and Ayo Edebiri. At first perplexing — are those supposed to be fireflies? — the random twinkles seemed too intermittent and odd to be purposeful. As soon as the first scene finished, it was clear that they weren’t doing what was expected, as neon lights gradually outlined the old Chicago home created by scenic designer Teresa L. Williams with color and gradual movement during scene transitions.

So one light had gone AWOL. Big deal. But as the show continued, it felt apropos for a solid production that feels slightly off-balance overall. The question is why.

The story hasn’t changed, but unless you’re completely unfamiliar with the play (which has, by dint of its small cast and single set, been catnip for regional and community theaters for the past two decades) and/or film, the work no longer has the advantage of catching us off-guard with its surprises. Ostensibly loaded with math, the play is actually a character chamber piece about Catherine (Edebiri), a young college dropout who’s worried she’s inherited the madness that had her late professor father (Cheadle) spending countless nights filling endless notebooks with new ideas and theories.

One of her father’s graduate students, Hal (Jin Ha), discovers that one of those notebooks — out of hundreds — contains a remarkable, game-changing proof. From that point forward, the question of who authored said proof becomes the play’s primary mystery, and a jumping-off point for all that follows.

Proof has an engaging story, and four talented actors are doing respectable jobs with their respective roles, especially the remarkable Kara Young, who’s won Tonys the past two seasons and manages to bring real vibrancy to Claire, Catherine’s older sister. But overall, a needed edge is missing, and one wonders if director Thomas Kail smoothed out too much in the rehearsal room. Cheadle and, to a lesser degree, Edebiri, never generate the familial sparks that make this play pop. Without that fizz, the theatrical equation that is Proof is merely enjoyable when it could be outstanding.