Wednesday, April 7th 11.30 am
Aula teledidattica padiglione E, DIST (via Opera Pia 13)

Alan Bundy, School of Informatics, University of Edinburgh (Scotland)


What is a proof ?


To those brought up in a logic-based tradition there seems to be a simple and clear definition of proof. But this is largely a 20th century invention; earlier proofs had a different nature. We will look particularly at the faulty proof of Euler's Theorem and Lakatos' rational reconstruction of the history of this proof. We will ask: how is it possible for the bugs in a faulty proof to remain undetected for several years -- even when counter-examples to it are known? How is it possible to have a proof about concepts that are only partially defined? And can we give a logic-based account of such phenomena?