Proof, Donmar Warehouse, London

Paltrow may shine on stage, but Broadway's mathematical hokum just doesn't add up

There's an old movie in which Mae West, as a rather improbable school ma'am, gives her charges an important arithmetic lesson. "Kids, there are only three things you need to know in life," she drawls. "One and one make two. Two and two make four. And four and four make ten – if you know how to work it right."

I was suddenly reminded of this scene at the London opening last night of David Auburn's Broadway hit Proof, another event that piquantly brackets together a blonde Hollywood icon and mathematical wizardry.

Considerably less curvaceous than Miss West, Gwyneth Paltrow has a distinct edge on her on the maths front in John Madden's skilfully inflected production of this Pulitzer Prize-winning drama. Looking incredibly young and at once defended and defenceless, the actress brings a hauntingly lost, twenty-five-going-on-fourteen quality to the role of Catherine, the daughter of a brilliant and newly deceased mathematician (Ronald Pickup).

Catherine has sacrificed her undergraduate maths career to looking after this troubled parent who, in bouts of severe mental instability and periods of remission, has a marked resemblance to John Nash, the schizophrenic hero of the movie A Beautiful Mind.

Now as she tries to come to terms with his death, Catherine also has to contend with a visit from her estranged currency-analyst, sister Claire, all overweening "concern" in Sara Stewart's very funny performance, and with the attention Richard Coyle's Hal, a geeky protégé of her father who is hoping to discover some mathematical gold in the notebooks he left behind.

If Catherine has cause to be suspicious of both of these intruders – the tidy-minded sibling who doubts her sanity; the ambitious graduate who has designs on her father's intellectual legacy – she proceeds to give them something to distrust in her turn. The title refers both to a ground-breaking "proof" in number theory found among the posthumous papers and to the difficulty of proving its authorship after Catherine claims that it is her independent work.

The play wants to contrast the inductive, tightly logical proofs possible in mathematics with the indeterminacy of attempts to prove things in the real world where leaps of faith may be necessary. But it blows its chances on both levels.

On the one hand, an over-clarifying flashback destroys, for the audience, the ambiv-alence of Catherine's assertions. And, unlike Stoppard's Arcadia or Frayn's Copenhagen, mathematical obsession features here as a melodramatic backdrop to lurid conundrums – has the daughter inherited her father's madness as well as his brilliance?– rather than as a profound preoccupation fully integrated into the emotional fabric of the drama.

Though Paltrow makes an arresting impression, the play patronises the audience by running a mile from any real discussion of the eponymous discovery. It may be quite a bit better than execrable A Beautiful Mind, but Proof is nonetheless just hokum-on-stilts. Less than the sum of its derivative parts, it is Broadway's mistaken idea of a truly penetrating play.