Paltrow slips into moody teenager mode – all sloping shoulders, sad eyes and deep sighs – for this screen version of the David Auburn play in which she also starred to some acclaim at the Donmar Warehouse in 2002. Paltrow is Catherine, the 25-year-old daughter of a formerly brilliant but latterly senile Chicago maths professor (Anthony Hopkins) who takes her father’s death badly. The subsequent discovery of an unpublished, brilliant maths paper raises the question of whether it was written by Catherine or by her late father. Her more worldly sister Claire (a good turn by Hope Davis) is certainly doubtful of her sister’s sanity – let alone her mathematical abilities. I’m told the original play was more ambiguous (and so more interesting), but there’s nothing to report here beyond a worn-out, inert portrayal of the boundaries between madness and genius. A road well-travelled.