Loss, love, blame, recrimination, genius, insanity, maths and paradigm-shifts� The snappy dialogue and complex relationships of American playwright David Auburn's Proof is brought to vivid life in the Progress Theatre's new production.

Particularly compelling is Anastasia Bristow's depiction of Catherine, a smart, sharp, sarcastic, yet vulnerable young woman who has spent years caring for her mentally ill mathemitican father and is struggling to reconcile her feelings about him, his work and her lost years in the immediate wake of his death. As she seeks to both avoid and process her feelings about their relationship, Catherine; her wilfully self-obsessed and business-like sister, Claire, played in a fittingly over-the-top style by Lauren Gilbert; and one of her father's protégés, the wilfully anti-nerd Harold, played convincingly by Matthew Drury, are thrown together by a shocking discovery.

Proof is an unexpectedly funny play which highlights the basic truth that very rarely do the loose ends in life neatly tie up, and even more rarely do people find the right words to say at the right time. And while some of the jokes and banter do sound a little familiar, the actors' delivery set the words apart and makes them funny all over again.

Played out on a set carefully constructed to convey a comfortable American homeliness - fittingly at odds with the uncomfortable emotions enacted onstage - with thoughtfully-chosen music and clever use of lights (and shadows), Progress Theatre's emotionally-charged production is one which is likely to stay with an audience long after they leave the theatre.

Proof runs until Saturday at Progress Theatre on The Mount, Christchurch Road, Reading. The play begins at 7.45pm and tickets cost £10 with £8 concessions.

Call 0118 960 60 60 or visit www.readingarts.com. to book.